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Solving ICSE Class 10 Physics Previous Year Question Papers ICSE Class 10 Physics Question Paper 2012 is the best way to boost your preparation for the board exams.

ICSE Class 10 Physics Question Paper 2012 Solved

Time: 1½ hours
Maximum Marks : 80

General Instructions:

• Answers to this paper must be written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question Paper.
• The time given at the head of this paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The intended marks for questions or parts of questions are given in brackets [].

SECTION – I (40 Marks)
(Attempt all questions from this section)

Question 1.
(a) (i) Define 1 kgf.
(ii) How is it related to the S.I. unit of force ? [2]
Answer.

1. One kilogram force is the force due to gravity on a mass of 1 kilogram.
2. 1 kgf = 9.8 N.

(b) (i) What are non-contact forces ?
(ii) How does the distance of separation between two bodies affect the magnitude of the non-contact force between them ? [2]
Answer.

1. The forces which act on bodies without being physically touched are called the non-contact forces.
2. It decreases with the increase in separation and increases as the separation decreases. These forces vary inversely as the square of distance of separation.

(c) A boy of mass 30 kg is sitting at a distance of 2 m from the middle of a see-saw. Where should a boy of mass 40 kg sit so as to balance the sea-saw? [2]
Answer.
According to principle of moments of force

W₁l₁ = W₂l₂
⇒ m₁l₁ = m₂l₂
⇒ 30 × 2 = 40 × l₂
⇒ l₂ = \(\frac{30 \times 2}{40}\)
= 1.5 m
(from fulcrum on the other side of see saw)

(d) (i) What is meant by the term ‘moment of force’ ?
(ii) If the moment of force is assigned a negative sign then will the turning tendency of the force be clockwise or anticlockwise ? [2]
Answer.

1. It is the turning effect of a force. The moment of a force is equal to the product of the magnitude of the force and the perpendicular distance of the line of action of force from the axis of rotation.
2. Clockwise.

(e) A ball is placed on a compressed spring. When the spring is released, the ball is observed to fly away.
(i) What form of energy does the compressed spring possess ?
(ii) Why does the ball fly away ? [2]

Answer.

1. Potential energy.
2. Because of change of potential energy of spring into the kinetic energy of the ball.

Question 2.
(a) (i) State the energy conversion taking place in a solar cell.
(ii) Give one disadvantage of using a solar cell. [2]
Answer:

1. Light energy converted into electrical energy.
2. The efficiency of conversion of solar energy to electrical energy is low.

(b) A body of mass 0.2 kg falls from a height of 10 m to a height of 6 m above the ground.
Find the loss in potential energy taking place in the body, [g = 10 ms^-2] [2]
Answer:
Loss of potential energy = mgh
= 0.2 × 10 × (10-6)
= 0.2 × 10 × 4
= 8 Joule

(c) (i) Define the term refractive index of a medium in terms of velocity of light.
(ii) A ray of light moves from a rare medium to a dense medium as shown in the diagram below. Write down the number of the ray which represents the partially reflected ray.

Answer:

1. Refractive index is defined the ratio of the speed of light in vacuum (or air) to the speed of light in the medium.
2. Ray 2.

(d) You are provided with a printed piece of paper. Using this paper how will you differentiate between a convex lens and a concave lens ? [2]
Answer:
Look at the printed piece of paper through both the lenses one after the other, holding the lens close to the paper. The lens through which letters appear to be magnified is convex lens.

(e) A ray of light incident at an angle of incidence T passes through an equilateral glass prism such that the refracted ray inside the prism is parallel to its base and emerges from the prism at an angle of emergence V.
(i) How is the angle of emergence V related to the angle of incidence ?
(ii) What can you say about the value of the angle of deviation in such a situation ? [2]
Answer:

1. ∠e = ∠i
2. The deviation suffered by the incident ray is minimum.

Question 3.
(a) (i) What is meant by ‘Dispersion of light’ ?
(ii) In the atmosphere which colour of light gets scattered the least ? [2]
Answer:

1. The phenomenon of splitting of white light into its constituent colours is known as dispersion of light.
2. Red, because of its large wavelength.

(b) Which characteristic of sound will change if there is a change in
(i) its amplitude
(ii) waveform. [2]
Answer:

1. Loudness
2. Pitch of a note or quality of a musical sound.

(c) (i) Name one factor which affects the frequency of sound emitted due to vibrations in an air column.
(ii) Name the unit used for measuring the sound level. [2]
Answer:

1. Frequency is inversely proportional to the length of the air column.
2. Decibel (db).

(d) An electrical appliance is rated at 1000 kVA, 220V. If the appliance is operated for 2 hours, calculate the energy consumed by the appliance in :
(i) kWh
(ii) joule
Answer:
Power = 1000 kVA
= 1000 kW
(as VA = W) (Power = VI)
V = 220 V
t = 2 hours
(i) Electric energy consumed
= 1000 kW x 2 h
= 2000 kWh

(ii) 2000 kWh = 3.6 × 10⁶ × 2000
= 7.2 × 10⁹ Joule

(e) Calculate the equivalent resistance between P and Q from the following diagram : [2]

Answer.
The equivalent circuit is

In series :
R_S = R₁ + R₂
= 10+ 10 = 20 Ω
In parallel:
\(\frac{1}{\mathrm{R}_{\mathrm{P}}}=\frac{1}{\mathrm{R}_{\mathrm{S}}}+\frac{1}{\mathrm{R}_2}\)
⇒ \(\frac{1}{R_P}=\frac{1}{20}+\frac{1}{5}\)
⇒ \(\frac{1}{\mathrm{R}_{\mathrm{P}}}=\frac{1+4}{20}\)
⇒ R_P = 4 Ω
Now, equivalent resistance = 3 + 4 + 2 = 9Ω

Question 4.
(a) (i) What is an a.c. generator or Dynamo used for ?
(ii) Name the principle on which it works.
Answer:

1. a.c. generator produces alternating voltage. It converts mechanical energy into electrical energy.
2. A generator works on principle of electromagnetic induction.

(b) Differentiate between heat capacity and specific heat capacity. [2]
Answer:

Heat capacity	Specific heat capacity
(i) It depends on the mass of the body.	(i) It does not depend on the mass of the body.
(ii) Its unit is JK-1. Heat capacity C’ = \(\frac{\mathrm{Q}}{\theta}\)	(ii) Its unit is Jkg-1 K1. S.H.C. or C = \(\frac{\mathrm{Q}}{m \theta}\)

(c) A hot solid of mass 60 g at 100°C is placed in 150 g of water at 20°C. The final steady temperature recorded is 25°C. Calculate the specific heat capacity of the solid. [Specific heat capacity of water = 4200 J kg^-1°C^-1] [2]
Answer:
Heat energy given by hot solid of specific heat capacity (c)
= 60 × c × (100° – 25°)
= 60 × c × 75
= 4500 c
Heat energy taken by water
= 150 × 4.2 × (25 – 20)
= 150 × 4.2 × 5
(c of water = 4200 Jkg^-1 k^-1. So given c = 4.2 Jg^-1K^-1)
If there is no loss of heat energy, then heat energy given = Heat energy taken
⇒4500 c = 150 × 4.2 × 5
⇒ c = \(\frac{150 \times 4.2 \times 5}{4500}\)
= 0.7 Jg^-1 k^-1

(d) (i) What is the value of the speed of gamma radiations in air or vacuum ?
(ii) Name a material which exhibits fluorescence when cathode rays fall on it.
Answer:

1. 3 × 10⁸ ms^-1.
2. Screen is coated with fluorescent material such as zinc sulphide containing a trace of manganese.

(e) Give any two important sources of background radiation.
Answer:
Sources of background radiation are :

1. Naturally occurring radio isotopes.
2. Radiation produced in the emission from nuclear power plants.

SECTION – II (40 Marks)
(Attempt any four questions from this Section)

Question 5.
(a) (i) Which of the following remains constant in uniform circular motion : Speed or Velocity or both ?
(ii) Name the force required for uniform circular motion. State its direction ? [3]
Answer:

1. Constant speed in a circular path.
2. Centripetal force. The direction of the force is along the radius towards the centre.

(b) (i) State the class of levers and the relative positions of load (L), effort (E) and fulcrum (F) in each of the following cases.
1. a bottle opener
2. Sugar tongs.
(ii) Why is less effort needed to lift a load over an inclined plane as compared to lifting the load directly ? [3]
Answer:

1. 1. Class II lever. Here, load is between the effort and the fulcrum.
   2. Class III lever. Here, effort is between load and fulcrum.
2. Because inclined plane is a simple machine and acts as a force multiplier. Hence, less effort is needed.

(c) (i) A moving body weighing 400 N possesses 500 J of kinetic energy.
Calculate the velocity with which the body is moving, (g = 10 ms^-2)
(ii) Under what condition will a set of gears produce
1. a gain in speed
2. a gain in torque. [4]
Answer:
(i) We know
W = mg
∴ m = \(\frac{\text { Weight }}{g}=\frac{400}{10}\) = 40 kg
K.E. = \(\frac{1}{2}\) mv²
⇒ v² = \(\frac{2 \times \mathrm{K} . \mathrm{E}}{m}\)
⇒ v² = \(\frac{2 \times 500}{40}\)
∴ v = \(\sqrt{\frac{100}{2}}=\frac{10}{2}\) = 5 ms^-1

(ii)

1. The driving gear has more number of teeth than the driven gear.
2. For a gain in torque, the number of teeth in the driven gear should be more than the number of teeth in the driver gear.

Question 6.
(a) (i) What is meant by the term ‘critical angle’ ?
(ii) How is it related to the refractive index of the medium ?
(iii) Does the depth of a tank of water appear to change or remain the same when viewed normally from above ? [3]
Answer:

1. Critical angle is the angle of incidence in the denser medium corresponding to which the angle of refraction in the rarer medium is 90°.
2. The refractive index p and critical angle C are related as μ = \(\frac{1}{\sin C}\)
3. Remains the same.

(b) A ray of light PQ is incident normally on the hypotenuse of a right-angled prism ABC as shown in the diagram given alongside :

(i) Copy the diagram and complete the path of the ray PQ till it emerges from the prism.
(ii) What is the value of the angle of deviation of the ray ?
(iii) Name an instrument where this action of the prism is used. [3]
Answer:

1. The path of the ray is as shown in the fig.
   
2. 180°
3. Periscope

(c) A converging lens is used to obtain an image of an object placed in front of it.
The inverted image is formed between F₂ and 2F₂ of the lens.
(i) Where is the object placed ?
(ii) Draw a ray diagram to illustrate the formation of the image obtained. [4]
Answer.

1. Beyond 2F₁
2. 

Question 7.
(a) (i) What is meant by Resonance?
(ii) State two ways in which Resonance differs from Forced vibrations. [3]
Answer:

1. Resonance is a special case of the forced vibrations. When the frequency of an externally applied periodic force on a body is equal to its natural frequency, the body readily begins to vibrate with an increased amplitude. This phenomenon is resonance.

2. Forced vibration	Resonance
   (i) The amplitude of vibration is usually small.	(i) The amplitude of vibration is very large.
   (ii) The vibrations of the body are not in phase with the external periodic force.	(ii) The vibrations of the body are in phase with the external periodic force.

(b) (i) A man standing between two cliffs produces a sound and hears two successive .echoes at intervals of 3 s and 4 s respectively. Calculate the distance between the two cliffs. The speed of sound in the air is 330 ms^-1.
(ii) Why will an echo not be hears when the distance between the source of sound and the reflecting surface is 10 m ? [3]
Answer:
(i) Let d₁ and d₂ is the distance of the two cliffs from the observer, then
3 = \(\frac{2 d_1}{v}=\frac{2 d_1}{330}\)
∴ d₁ = \(\frac{3 \times 330}{2}\)
= 495 m
Similarly, for the second cliff
4 = \(\frac{2 d_2}{330}\)
d₁ = \(\frac{4 \times 330}{2}\)
= 660 m
∴ Distance between the two cliffs
= 495 + 660 = 1155 m

(ii) No echo will be heard when the distance between source and reflector is 10 m because it is less than the minimum required distance of 17 m.

(c) The diagram alongside shows the displacement-time graph for a vibrating body.

(i) Name the type of vibrations produced by the vibrating body.
(ii) Give one example of a body producing such vibrations.
(iii) Why is the amplitude of the wave gradually decreasing ?
(iv) What will happen to the vibrations of the body after some time ?
Answer:

1. Damped vibrations.
2. When a slim branch of a tree is pulled and then released.
3. The amplitude of motion decreases due to the frictional force which the surrounding medium exerts on the body vibrating in it.
4. Body will stop vibrating.

Question 8.
(a) (i) A cell is sending current in an external circuit. How does the terminal voltage compare with the e.m.f. of the cell ?
(ii) What is the purpose of using a fuse in an electrical circuit ?
(iii) What are the characteristic properties of fuse wire ? [3]
Answer:

1. Terminal voltage < emf i.e., E > V in closed circuit, emf is equal to terminal voltage when no current is drawn.
2. Fuse is used to limit the current in an electric circuit. Its purpose is to provide safeguards to the circuit and the appliances connected in that circuit from being damaged.
3. Fuse wire is made up of a material of high resistivity and of low melting point so that it may easily melt due to overheating when current in excess of the prescribed limit passes through it.

(b) (i) Write an expression for the electrical energy spent in the flow of current through an electrical appliance in terms of I, R and t.
(ii) At what voltage is the alternating current supplied to our houses ?
(iii) How should the electric lamps in a building be connected ? [3]
Answer:

1. W = I² Rt.
2. 220 V.
3. In parallel.

(c) Three resistors are connected to a 6 V battery as shown in the figure given alongside :

Calculate:
(i) the equivalent resistance of the circuit.
(ii) total current in the circuit.
(iii) potential difference across the 7.2 Ω resistor.
Answer:
(i) In parallel.
\(\frac{1}{R_P}=\frac{1}{R_1}+\frac{1}{R_2}\)
⇒ \(\frac{1}{R_P}=\frac{1}{8}+\frac{1}{12}\)
⇒ \(\frac{1}{R_P}=\frac{3+2}{24}\)
⇒ R_P = \(\frac{24}{5}\) = 4.8 Ω
Equivalent resistance (R)
= 7.2+ 4.8
= 12 Ω
(ii) Current = \(\frac{\mathrm{V}}{\mathrm{R}}\)
= \(\frac{6}{12}\) = 0.5 A
(iii) Potential difference across the 7.2 Ω
= 7.2 × 0.5
= 3.6 V

Question 9.
(a) (i) Write an expression for the heat energy liberated by a hot body.
(ii) Some heat is provided to a body to raise its temperature by 25°C.
What will be the corresponding rise in temperature of the body as shown on the kelvin scale ?
(iii) What happens to the average kinetic energy of the molecules as ice melts at 0°C ?
Answer:

1. Q = mass (m) × specific heat × fall of temperature.
2. 25 K
3. Average kinetic energy remains the same.

(b) A piece of ice at 0°C is heated at a constant rate and its temperature recorded at regular intervals till steam is formed at 100°C. Draw a temperature – time graph to represent the change in phase. Label the different parts of your graph. [3]
Answer:
Since temperature remains the same.

1. AB represents the change of phase when ice at 0°C changes to water at 0°C (although time increases from 0 to t₁)
2. BC represents the change in temperature from 0°C to 100°C when water increases its temperature and time reaches from t₁ to t₂.
3. CD represents the change of phase when water at 100°C changes to steam at 100°C (no change in temp.) but time changes from t₂ to t₄ as L of vaporization of steam is 2268 J/g.

(c) 40 g of ice at 0°C is used to bring down the temperature of a certain mass of water at 60°C to 10°C. Find the mass of water used.
[Specific heat capacity of water = 4200 J kg^-1 °C^-1]
[Specific latent heat of fusion of ice = 336 × 10³ J kg^-1] [4]
Answer:
According to principle of calorimetry
Heat lost by water = Heat gained by ice to melt + Heat gained by water to reach to 10°C.
Heat Lost by water = m × 4.2 × (60 – 10)
= 210 m
(where mass of water = m)
Heat gained by ice to melt,
mL= 40 × 336= 13440 J
Heat gained by water to raise its temperature to 10°C
= 40 × 4.2 × 10 = 1680 J
So 210 m = 13440+ 1680
(Given c of water = 4200 J kg/k = 4.2 J/g/k,
= 15120
L of ice = 336 × 10³ J/kg = 336 J/g)
m = \(\frac{15120}{210}\) = 72 g

Question 10.
(a) The diagram alongside shows a current carrying loop or a circular coil passing through a sheet of cardboard at the points M and N. The sheet of cardboard is sprinkled uniformly with iron filings.

(i) Copy the diagram and draw an arrow on the circular coil to show the direction of current flowing through it.
(ii) Draw the pattern of arrangement of the iron filings when current is passed through the loop. [3]
Answer:

(b) (i) Draw a simplified labelled diagram of a hot cathode ray tube.
(ii) Name a common device where a hot cathode ray tube is used. [3]
Answer:

1. 
2. A hot cathode ray is used as a picture tube in television and in a cathode ray oscilloscope.

(c) A certain nucleus X has a mass number 14 and atomic number 6. The nucleus X changes to ₇Y¹⁴ after the loss of a particle.
(i) Name the particle emitted.
(ii) Represent this change in the form of an equation.
(iii) A radioactive substance is oxidized. What change would you expect to take place in the nature of its radioactivity 1 Give a reason for you answer. [4]
Answer.

1. The emitted particle is an electron.
2. The required equation is
   6 X¹⁴ → ₇Y¹⁴ + \({ }_{-1}^0 e\)
3. Oxidation does not alter the radioactivity since the nucleus remains the same.

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Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2017  is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2017 Solved

Time: 2 hours
Maximum Marks: 80

General Instructions:

• Answers to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question Paper.
• The time given at the head of this paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The intended marks for questions or parts of questions are given in brackets [ ].

Section – I (40 MARKS)
(Attempt all questions from this Section)

Question 1.
(a) Fill in the blanks from the choices given in brackets. [5]
(i) The energy required to remove an electron from a neutral isolated gaseous atom and convert it into a positively charged gaseous ion is called ________ .
(electron affinity, ionisation potential, electronegativity)
(ii) The compound that does not have a lone pair of electrons is ________ . (water, ammonia, carbon tetrachloride)
(iii) When a metallic oxide is dissolved in water, the solution formed has a high concentration of ________ ions. (H⁺, H₃O⁺, OH^–)
(iv) Potassium sulphite on reacting with hydrochloric acid releases ________ gas. (Cl₂, SO₂, H₂S)
(v) The compound formed when ethene reacts with Hydrogen is ________ . (CH₄, C₂H₆, C₃H₈)
Answer:
(i) Ionisation potential
(ii) Carbon tetrachloride
(iii) OH^–
(iv) SO₂
(v) C₂H₆

(b) Choose the correct answer from the options given below : [5]
(i) A chloride which forms a precipitate that is soluble in excess of ammonium hydroxide, is:
(A) Calcium chloride
(B) Ferrous chloride
(C) Ferric chloride
(D) Copper chloride
Answer:
(D) copper chloride

(ii) If the molecular formula of an organic compounds is C₁₀H₁₈ it is:
(A) alkene
(B) alkane
(C) alkyne
(D) Not a hydrocarbon
Answer:
(C) alkyne

(iii) Which of the following is a common characteristic of a covalent compound?
(A) high melting point
(B) consists of molecules
(C) always soluble in water
(D) conducts electricity when it is in the molten state
Answer:
(B) consists of molecules

(iv) To increase the pH value of a neutral solution, we should add:
(A) an acid
(B) an acid salt
(C) an alkali
(D) a salt
Answer:
(C) an alkali

(v) Anhydrous iron (III) chloride is prepared by:
(A) direct combination
(B) simple displacement
(C) decomposition
(D) neutralization
Answer:
(A) direct combination

(c) Identify the substance underlined, in each of the following cases: [5]
(i) Cation that does not form a precipitate with ammonium hydroxide but forms one with sodium hydroxide,
Answer:
Copper

(ii) The electrolyte used for electroplating an article with silver.
Answer:
Sodium argento cyanide

(iii) The particles present in a liquid such as kerosene, that is a non-electrolyte.
Answer:
molecules

(iv) An organic compound containing – COOH functional group.
Answer:
carboxylic acid

(v) A solid formed by reaction of two gases, one of which is acidic and the other basic in nature.
Answer:
Ammonium chloride

(d) Write a balanced chemical equation for each of the following:
(i) Action of cold and dilute nitric acid on copper.
Answer:
3Cu + 8HNO₃ → 3CU(NO₃)₂ + 4H₃O + 2NO↑

(ii) Reaction of ammonia with heated copper oxide.
Answer:
2NH₃ + 3CuO → 3Cu + 3H₂O + N₂↑

(iii) Preparation of methane from iodomethane.
Answer:
CH₃I + 2[H] → CH₄ + HI

(iv) Action of concentrated sulphuric acid on sulphur.
Answer:
S + 2H₂SO₄ → 3SO₂ + 2H₂O

(v) Laboratory preparation of ammonia from ammonium chloride.
Answer:
2NH₄Cl + Ca(OH)₂ → CaCl₂ + 2H₃O + 2NH₃

(e) State one relevant observation for each of the following reactions: [5]
(i) Addition of ethyl alcohol to acetic acid in the presence of concentrated sulphuric acid.
Answer:
Fruity smell due to formation of ester is there.

(ii) Action of dilute hydrochloric acid on iron (II) sulphide.
Answer:
Rotten egg smell due to formation of hydrogen sulphide.

(iii) Action of sodium hydroxide solution on ferrous sulphate solution.
Answer:
Dirty green precipitates of ferrous hydroxide are formed.

(iv) Burning of ammonia in air.
Answer:
Yellowish green flame is produced when ammonia bums in air.

(v) Action of concentrated sulphuric acid on hydrated copper sulphate.
Answer:
Hydrated copper sulphate which is blue in colour change to anhydrous copper sulphate which is white in colour.

(f) (i) Draw the structural formula for each of the following: [5]
1. 2, 3 – dimethyl butane
2. diethyl ether
3. propanoic acid
Answer:

(ii) From the list of terms given, choose the most appropriate term to match the given description.
(calcination, roasting, pulverisation, smelting)
1. Crushing of the ore into a fine powder.
2. Heating of the ore in the absence of air to a high temperature.
Answer:
1. Pulverisation
2. Calcination

(g) (i) Calculate the number of gram atoms in 4.6 grams of sodium (Na = 23). [5]
(ii) Calculate the percentage of water of crystallization in CuSO₄.5H₂O
(H = 1, O = 16, S = 32, Cu = 64)
(iii) A compound of X and Y has the empirical formula XY₂. Its vapour density is equal to its empiricial formula weight. Determine its molecular formula.
Answer:
(i) 23 g of sodium → 1 gram atom
1 g of sodium → \(\frac{1}{23}\) gram atom
4.6 g of sodium → \(\frac{1}{23} \times \frac{4.6}{10}=\frac{2}{100}\) = 0.02 g atoms

(ii) Molecular mass of CuSO₄.5H₂O
= [64 + 32 + 4 × 16] + 5[18]
= [64 + 32 + 64] + [90]
= 160 + 90 = 250
% of water of crystallisation = \(\frac{90}{250}\) × 100 = 36%

(iii) E.F.= XY₂ E.F.W.= V.D.
M.W.= 2 × V.D.
M.W.= 2 × [E.F.W.]
So molecular formula = (XY₂)₂ = X₂Y₄

(h) Match the atomic number 2, 4, 8, 15, and 19 with each of the following: [5]
(i) A solid non-metal belonging to the third period.
(ii) A metal of valency 1.
(iii) A gaseous element with valency 2.
(iv) An element belonging to Group 2.
(v) A rare gas.
Answer:
(i) → 15
(ii) → 19
(iii) → 8
(iv) → 4
(v) → 2

Section – II (40 Marks)
(Attempt any four questions from this Section)

Question 2.
(a) Arrange the following as per the instruction given in the brackets: [4]
(i) He, Ar, Ne (Increasing order of the number of electron shells)
(ii) Na, Li, K (Increasing ionisation energy)
(iii) F, Cl, Br (Increasing electronegativity)
(iv) Na, K, Li (increasing atomic size)
Answer:

(b) State the type of Bonding in the following molecules: [2]
(i) Water
(ii) Calcium oxide
Answer:
(i) Water – Covalent bond
(ii) Calcium oxide – Ionic bond

(c) Answer the following questions: [2]
(i) How will you distinguish between ammonium hydroxide and sodium hydroxide using copper sulphate solutions?
(ii) How will you distinguish between dilute hydrochloric acid and dilute sulphuric acid using lead nitrate solution?
Answer:

NaOH solution	NH4OH solution
On adding sodium hydroxide to copper sulphate, pale blue ppts. will appear which will not be soluble is excess.	On adding ammonium hydroxide to copper sulphate, pale blue ppts. will appear which will be soluble in excess.

(d) Identify the salts P and Q from the observations given below: [2]
(i) On performing the flame test salt P produces a lilac coloured flame and its solution gives a white precipitate with silver nitrate solution, which is soluble in ammonium hydroxide solution.
(ii) When dilute HCl is added to a salt Q, a brisk effervescence is produced and the gas turns lime water milky.
When NH₄OH solution is added to the above mixture (after adding dilute HCl), it produces a white precipitate which is soluble in excess NH₄OH solution.
Answer:
(i) KCl
(ii) ZnCO₃

Question 3.
(a) Draw an electron dot diagram to show the formation of each of the following compounds: [4]
(i) Methane
(ii) Magnesium chloride
[H = 1, C = 6, Mg = 12, Cl = 17]
Answer:
(i)

(ii) Magnesium chloride MgCl₂

(b) State the observations at the anode and at the cathode during the electrolysis of: [4]
(i) fused bromide using graphite electrodes.
(ii) copper sulphate solution using copper electrodes.
Answer:
(i) At anode :
Dark reddish brown fumes of bromine evolve at the anode.

At cathode:
Greyish white metal lead is formed on the cathode.

(ii) At anode:
Anode decreases in size due to the formation of copper ions.

At cathode:
Reddish brown copper is deposited

(c) Select the ion in each case, that would get selectively discharged from the aqueous mixture of the ions listed below: [2]
(i) SO₄^2-, NO₃^–, and OH^–
(ii) Pb²⁺, Ag⁺ and Cu²⁺
Answer:
(i) OH^–
(ii) Ag⁺

Question 4.
(a) Certain blank spaces are left in the following table and these are labelled as A, B, C, D and E. Identify each of them. [5]

Answer:
A → Below 200°C (NaHSO₄)
Above 200°C (Na₂SO₄)
B → Upward displacement of air
C → Magnesium nitride (Mg₃N₂) and water
D → Calcium oxide
E → Downward displacement of air

(b) Write balanced chemical equations to show: [3]
(i) The oxidizing action of cone, sulphuric acid on carbon.
(ii) The behaviour of H₂SO₄ as an acid when it reacts with magnesium.
(iii) The dehydrating property of cone, sulphuric acid with sugar.
Answer:
(i) C + 2H₂SO₄ → 2H₂O + CO₂ + 2SO₂
(ii) Mg + H₂SO₄ → MgSO₄ + H₂↑
(iii) C₁₂H₂₂O₁₁ + H₂SO₄ → 12C+ 11H₂O

(c) Write balanced chemical equations to show how SO₃ is converted to sulphuric acid in the contact process. [2]
Answer:
SO₃ + H₂SO₄ → H₂S₂O₇ (oleum)
H₂S₂O₇ + H₂O → 2H₂SO₄

Question 5.
(a) (i) Propane burns in air according to the following equation: [4]
C₃H₈ + 5O₂ -* 3CO₂ + 4H₂O.
What volume of propane is consumed on using 1000 cm3 of air, considering only 20% of air contains oxygen?
(ii) The mass of 11.2 litres of a certain gas at s.t.p. is 24 g. Find gram molecular mass of the gas.
Answer:
(i) C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
1 vol. 5 vol.
If air is 100, then oxygen is 20%
If air is 100cm3, then oxygen is \(\frac{20}{100}\) × 1000 = 200 cm³
If 5 vol. of oxygen is used, then propane is 1 vol.
1 vol. of oxygen is used, then propane is \(\frac{1}{5}\) vol.
If 200 cm³ of oxygen is used, then propane is \(\frac{1}{5}\) × 200 cm³ = 40 cm³

(ii) 11.2 litres of a certain gas at s.t.p. is 24
1 litre of a certain gas at s.t.p. is \(\frac{24}{11.2}\)
22.4 litres of a certain gas at s.t.p. is
\(\frac{24}{11.2}\) × 22.4 L = 48 g

(b) A gas cylinder can hold 1 kg of hydrogen at room temperature and pressure: [4]
(i) Find the number of moles of hydrogen present.
(ii) What weight of CO₂ can the cylinder hold under similar conditions of temperature and pressure? (H = 1, C = 12, O = 16)
(iii) If the number of molecules of hydrogen in the cylinder is x, calculate the number of CO₂ molecules in the cylinder under the same conditions of temperature and pressure.
(iv) State the law that helped you to arrive at the above result.
Answer:
(i) Weight of hydrogen = 2 × 1 g = 2 g
2 g of hydrogen corresponds to 1 mole of hydrogen
1 g of hydrogen corresponds to \(\frac{1}{2}\) mole of hydrogen
1000 g of hydrogen corresponds to \(\frac{1}{2}\) × 1000 g mole of H₂ = 500 moles

(ii) 1 mole of H₂ occupy 22.4 L
500 mole of H₂ occupy = 22.4 × 500
By Avogadro’s law the volume occupied by CO₂ will be same
Weight of CO₂ = 12 + 2 16 = 44 g
22.4 L will weigh 44 g
1 L will weigh \(\frac{44}{22.4}\)
22.4 × 500 L will weigh \(\frac{44}{22.4}\) × 22.4 × 500
= 22000 g = 22 kg

(iii) X (Because of Avogadro’s law)

(iv) Avogadro’s law

(c) Write a balanced chemical equation for the preparation of each of the following salts: [2]
(i) Copper carbonate
(ii) Ammonium sulphate crystals
Answer:
(i) CU(NO₃)₂ + Na₂CO₃ → CuCO₃ + 2NaNO₃
(ii) 2NH₄Cl + H₂SO₄ → (NH₄)₂ SO₄ + 2HCl

Question 6.
(a) Give a balanced chemical equation for each of the following: [4]
(i) Action of cone, nitric acid on sulphur.
(ii) Catalytic oxidation of ammonia.
(iii) Laboratory preparation of nitric acid.
(iv) Reaction of ammonia with nitric acid.
Answer:

(b) Identify the term or substance based on the descriptions given below:
(i) Ice like crystals formed on cooling an organic acid sufficiently.
(ii) Hydrocarbon containing a triple bond used for welding purposes.
(iii) The property by virtue of which the compound has the same molecular formula but different structural formulae.
(iv) The compound formed where two alkyl groups are linked by — C- group.
Answer:
(i) Acetic acid
(ii) Acetylene
(iii) Isomerism
(iv) Ketone

(c) Give a balanced chemical equation for each of the following: [2]
(i) Preparation of ethane from sodium propionate.
(ii) Action of alcoholic KOH on bromoethane.
Answer:

Question 7.
(a) Name the following: [4]
(i) The process of coating of iron with zinc.
(ii) An alloy of lead and tin that is used in electrical circuits.
(iii) An ore of zinc containing its sulphide.
(iv) A metal oxide that can be reduced by hydrogen.
Answer:
(i) Galvanisation
(ii) Solder
(iii) Zinc blende
(iv) Copper oxide

(b) Answer the following questions with respect to the electrolytic process in the extraction of aluminum: [3]
(i) Identify the components of the electrolyte other than pure alumina and the role played by each.
(ii) Explain why powdered coke is sprinkled over the electrolytic mixture.
Answer:
(i) Alumina (Al₂O₃) : It is the main compound yielding aluminium.
Cryolite (Na₃AlF₆): It acts as a solvent and lower the fusion temperature from 2050°C to 950°C.
Fluorspar (CaF₂): It acts as a solvent and increases the conductivity of electrolytic mixture.

(ii) Layer of powdered coke is sprinkled over the surface of the electrolytic mixture to prevent the heat loss by radiation and prevents carbon anode from burning in air.

(c) Complete the following by selecting the correct option from the choices given: [3]
(i) The metal which does not react with water or dilute H₂SO₄ but reacts with concentrated H₂SO₄ is __________ . (Al/Cu/Zn/Fe)
(ii) The metal whose oxide, which is amphoteric, is reduced to metal by carbon reduction _________ . (Fe/Mg/Pb/Al)
(iii) The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is __________ . (Al/Na/Mg/K)
Answer:
(i) Cu
(ii) Pb
(iii) Mg

Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2016 is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2016 Solved

Time : 2 hour
Maximum Marks: 40

General Instructions:

• Answers to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question Paper.
• The time given at the head of this paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The intended marks for questions or parts of questions are given in brackets [ ].

SECTION -1 (40 MARKS)
(Attempt all questions from this Section)

Question 1.
(a) Fill in the blanks with the choices given in brackets. [5]
(i) Metals are good ________ (oxidizing agents/reducing agents) because they are electron ________ (acceptors/donors).
(ii) Electrovalent compounds have ________ (high/low) melting points.
(iii) Higher the pH value of a solution, the more ________ (acidic/alkaline) it is.
(iv) ________ (AgCl / PbClj), a white precipitate is soluble in excess NH4OH.
(v) Conversion of ethene to ethane is an example of ________ (hydration/hydrogenation).
Answer:
(i) reducing agents; donors
(ii) high
(iii) alkaline
(iv) AgCl (because of formation of diammine silver chloride)
(v) hydrogenation

(b) Choose the correct answer from the options given below : [5]
(i) An element with the atomic number 19 will most likely combine chemically with the element whose atomic number is :
(A) 17
(B) 11
(C) 18
(D) 20
Answer:
(A) 17

(ii) The ratio between the number of molecules in 2 g of hydrogen and 32 g of oxygen is :
(A) 1:2
(B) 1 : 0.01
(C) 1:1
(D) 0.01 : 1 [Given that H = 1, O = 16]
Answer:
(C) 1:1

(iii) The two main metals in Bronze are :
(A) Copper and zinc
(B) Copper and lead
(C) Copper and nickel
(D) Copper and tin
Answer:
(D) Copper and tin

(iv) The particles present in strong electrolytes are :
(A) only molecules
(B) mainly ions
(C) ions and molecules
(D) only atoms
Answer:
(B) mainly ions

(v) The main of the Fountains Experimeter is to prove that :
(A) HCl turns blue litmus red
(B) HCl is denser than air
(C) HCl is highly soluble in water
(D) HCl fumes in moist air.
Answer:
(C) HCl is highly soluble in water

(c) Write balanced chemical equations for each of the following : [5]
(i) Action of warm water on AIN.
(ii) Action of hot and concentrated Nitric acid on copper.
(iii) Action of Hydrochloric acid on sodium bicarbonate.
(iv) Action of dilute Sulphuric acid on Sodium Sulphite.
(v) Preparation of ethanol from Ethyl Chloride.
Answer:
(i) AIN + 3H₂O → Al(OH)₃ + NH₃↑
(ii) Cu + 4HNO₃ → Cu(NO₃)₂ + 2H₂O + 2NO₂↑
(iii) NaHCO₃ + HCl → NaCl + H₂O + CO₂↑
(iv) Na₂SO₃ + H₂SO₄ → Na₂SO₄ + H₂O + S0₂↑
(v) C₂H₅Cl + NaOH(aq) → C₂H₅OH + NaCl

(d) State your observations when : [5]
(i) Dilute Hydrochloric acid is added to Lead nitrate sodium and the mixture is heated.
(ii) Barium chloride solution is mixed with Sodium Sulphate Solution.
(iii) Concentrated Sulphuric acid is added to Sugar Crystals.
(iv) Dilute Hydrochloric acid is added to Copper carbonate.
(v) Dilute Hydrochloric acid is added to Sodium thiosulphate.
Answer:
(i)

When dilute hydrochloric acid is added to lead nitrate white precipitates of lead chloride are formed.
(ii)

When sodium sulphate is mixed with barium chloride. White coloured precipitates of Barium sulphate are formed.
(iii)

When conc. sulphuric acid is added to sugar crystals black spongy mass (sugar charcoal) is formed.
(iv)

When dilute hydrochloric acid is added to copper carbonate brisk effervescence due to the liberation of carbon dioxide is observed.
(v)

When dilute hydrochloric acid is added to sodium thiosulphate yellow residue (due to formation of sulphur) is formed and a gas with choking odour is formed.

(e) Identify the term/substance in each of the following : [5]
(i) The tendency of an atom to attract electrons to itself when combined in a compound.
(ii) The method used to separate ore from gangue by preferential wetting.
(iii) The catalyst used in the conversion of ethyne to ethane.
(iv) The type of reactions alkenes undergo.
(v) The electrons present in the outermost shell of an atom.
Answer:
(i) Electronegativity
(ii) Froth flotation process
(iii) Nickel or platinum or palladium
(iv) Addition reactions
(v) Valence electrons

(f) (i) A gas of mass 32 gms has a volume of 20 litres at S.T.P. Calculate the gram molecular weight of the gas. [5]
(ii) How much Calcium oxide is formed when 82 g of calcium nitrate is heated ? Also find the volume of nitrogendioxide evolved :
2Ca(NO₃)₂ → 2CaO + 4NO₂ + O₂
(Ca = 40, N = 14, O = 16)
Answer:
(i) 20 litres at S.T.P. weighs equal to 32 g
1 litre at S.T.P. weighs equal to \(\frac{32}{20}\) g
22.4 litres at S.T.P.
Weighs equal to \(\frac{32}{20}\) × 22.4 = 35.84 g

328 g will decompose to form 112 g of CaO
1 g will decompose to form \(\frac{112}{328}\)g of CaO
82g will decompose to form \(\frac{112}{328}\) × 82 g = 28 g of CaO
328 g will decompose to form 4 vol of N02 328 g will decompose to form 4 x 22.4 l of NO₂
1 g will decompose to form \(\frac{4 \times 22.4}{328}\) of NO₂
82 g will decompose to form = \(\frac{4 \times 22.4}{328}\) x 82
= 22.4 l of NO₂
= 1 Volume of NO₂

(g) Match the salts given in Column I with their method of preparation given in Column II :

Column I	Column II
(i) Pb(NO3)2 from PbO	(A) Simple displacement
(ii) MgCl2 from Mg	(B) Titration
(iii) FeCl3 from Fe	(C) Neutralization
(iv) NaNO3 from NaOH	(D) Precipitation
(v) ZnCO3, from ZnSO4	(E) Combination

Answer:

Column I	Column II
(i) Pb(NO3)2 from PbO	(C) Neutralization
(ii) MgCl2 from Mg	(A) Simple displacement
(iii) FeCl3 from Fe	(E) Combination
(iv) NaNO3 from NaOH	(B) Titration
(v) ZnCO3, from ZnSO4	(D) Precipitation

(h) (i) Write the IUPAC names of each of the following :

(ii) Rewrite the following sentences by using the correct symbol > (greater than) or < (less than) in the blanks given :
1. The ionization potential of Potassium is ________ that of Sodium.
2. The electronegativity of Iodine is ________ that of Chlorine.
Answer:
(i) 1. prop – 1 – ene
2. but – 2 – yne
3. ethanal

(ii) 1. < (less than)
2. < (less than)

SECTION – II (40 MARKS)
(Attempt any four questions from this Section)

Question 2.
(a) Use the letters only written in the Periodic Table Given below to answer the questions that follow : [4)

(i) State the number of valence electrons in atom J.
(ii) Which element shown forms ions with a single negative charge?
(iii) Which metallic element is more reactive than R?
(iv) Which element has its electrons arranged in four shells?
Answer:
(i) J → (5 valence electrons)
(ii) M → (7 valence electrons) so it forms a uninegative ion
(iii) T
(iv) T

(b) Fill in the blanks by selecting the correct word from the brackets :
(i) If an element has a low ionization energy then it is likely to be ________ (metallic / non-rnetallic).
(ii) If an element has seven electrons in its outermost shell then it is likely to have the ________ (largest / smallest) atomic size among all the elements in the same period.
Answer:
(i) metallic
(ii) smallest

(c) The following table shows the electronic configuration of the elements W, X, Y, Z :

Answer the following questions based on the table above
(i) What type of Bond is formed between :
1. W and X
2. Y and Z

(ii) What is the formula of the compound formed between : [2]
1. X and Z
2. W and X
Answer:
(i) 1. electrovalent bond
2. covalent bond

Question 3.
(a) Write a balanced chemical equation for each of the following : [3]
(i) Burning of ethane in plentiful supply of air.
(ii) Action of water on Calcium carbide.
(iii) Heating of Ethanol at 170°C in the presence of cone. Sulphuric acid.
Answer:
(i) C₂H₆ + \(\frac{7}{2}\)O₂ → 2CO₂ + 3H₂O
2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O
(ii) CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂ ↑

(b) Give the structural formulae of each of the following : [3]
(i) 2-methyl propane
(ii) Ethanoic acid
(iii) Butan – 2 – ol
Answer:

(c) Equation for the reaction when compound A is bubbled through bromine dissolved in carbon tetrachloride is as follows : [2]

(i) Draw the structure of A.
(ii) State your observationduring this reaction.
Answer:

(ii) Bromine water turns colourless.

(d) Fill in the blanks using the appropriate words given below : [2]
(Sulphur dioxide, Nitrogen dioxide, Nitric oxide, Sulphuric acid)
(i) Cold, dilute, nitric acid reacts with copper to given
(ii) Hot, concentrated nitric acid reacts with sulphur to form
Answer:
(i) nitric oxide
(ii) nitrogen dioxide

Question 4.
(a) Identify the gas evolved and give the chemical test in each of the following cases : [2]
(i) Dilute hydrochloric acid reacts with sodium sulphuric.
(ii) Dilute hydrochloric acid reacts with iron (II) sulphide.
Answer:
(i)

Chemical test: Sulphur dioxide decolorises potassium permanganate solution.
(ii)

Chemical test: Hydrogen sulphide turns lead acetate paper black.

(b) State your observations when ammonium hydroxide solution is added drop by drop and then in excess to each of the following solutions : [2]
(i) copper sulphate solution
(ii) zinc sulphate solution
Answer:
(i)

Pale blue precipitates are formed and then these precipitates dissolve in excess of ammonium hydroxide to form deep blue solution.
(ii)

When ammonium hydroxide is added drop by drop white gelatinous precipitate of zinc hydroxide is formed and on adding excess of ammonium hydroxide colourless solution is formed.

(c) Write equations for the reactions taking place at the two electrodes (mentioning clearly the name of the electrode) during the electrolysis of : [4]
(i) Acidified copper sulphate solution with copper electrodes.
(ii) Molten lead bromide with inert electrodes.
Answer:
(i) Dissociation reaction :

At cathode (negative terminal of battery)
Cu²⁺ + 2e^– → Cu(s)
copper metal gets deposited

At anode (positive terminal of battery)
Cu → Cu²⁺ + 2e^–
Copper metal gets converted into ions

(ii) Dissociation reaction

At cathode (negative terminal of battery)
Pb²⁺ + 2e^– → Pb
Lead metal is obtained in molten state
At anode (positive terminal of battery)
Br^– – le^– → Br
Br + Br → Br₂
Reddish brown vapours of bromine are formed

(d) (i) Name the product formed at the anode during the electrolysis of acidified water using platinum electrodes. [2]
(ii) Name the metallic ions that should be present in the electrolyte when an article made of copper is to be electroplated with silver.
Answer:
(i) Oxygen
(ii) Silver ions

Question 5.
(a) A gas cylinder contains 12 × 10²⁴ molecules of oxygen gas.
If Avogadro’s number is 6 × 10²³ ; Calculate :
(i) the mass of oxygen present in the cylinder.
(ii) the volume of oxygen at S.T.P. present in the cylinder. [O = 16]
Answer:
(i) 6 × 10²³ molecules are present the mass is 32 g

12 × 10²⁴ molecules are present than the mass is 32
\(\frac{32}{6 \times 10^{23}}\) × 12 × 10²⁴ = 32 × 20 = 640 g

(ii)

1 g will occupy a volume of \(\frac{22.4}{32}\)
640 g will occupy a volume of \(\frac{22.4}{32}\) × 640 = 448 l

(b) A gaseous hydrocarbon contains 82.76% of carbon. Given that its vapours density is 29, find its molecular formula. [C = 12, H = 1]
Answer:

E.F. = C₂H₅
E.F.M. = 12 × 2 + 5 × 1 = 24 + 5 = 29
V.D. = 29
M.M. = 2 × V.D. = 2 × 29 = 58
n = \(\frac{\text { M.M }}{\text { E.F.M }}=\frac{58}{29}\) = 2
Molecular formula = (C₂H₅)₂ = C₄H₁₀

(c) The equations 4NH₃ + 5O₂ → 4NO + 6H₂O, represents the catalytic oxidation of ammonia. If 100 cm3 of ammonia is used calculate the volume of oxygen required to oxidise the ammonia completely. [3]
Answer:

4 vol requires 5 vol
1 vol requires \(\frac{5}{4}\)
100 cm³ requires \(\frac{5}{4}\) × 100 = 125 cm³ of O₂

(d) By drawing an electron dot diagram show the formation of Ammonium Ion [Atomic No. : N = 7 and H = 1]
Answer:
N(7) → 2, 5 H(l) → 1

Question 6.
(a) Name the gas evolved when the following mixtures are heated : [2]
(i) Calcium hydroxide and Ammonium Chloride.
(ii) Sodium Nitrite and Ammonium Chloride.
Answer:
(i) Ammonia
(ii) Nitrogen

(b) Write balanced chemical equations for each of the following : [2]
(i) When excess of ammonia is treated with chlorine.
(ii) An equation to illustrate the reducing nature of ammonia.
Answer:
(i) 8NH₃ + 3Cl₂ → 6NH₄Cl + N₂
(ii) 3CuO + 2NH₃ → 3Cu + N₂ + 3H₂O

(c) A, B, C and D summarize the properties of sulphuric acid depending on whether it is dilute or concentrated. |3]
A = Typical acid property
B = Non-volatile acid
C = Oxidizing agent
D = Dehydrating agent
Choose the property (A, B, C or D) depending on which is relevant to each of the following :
(i) Preparation of Hydrogen chloride gas.
(ii) Preparation of Copper sulphate from copper oxide.
(iii) Action of cone. Sulphuric acid on Sulphur.
Answer:
(i) → B
(ii) → A
(iii) → C

(d) Give reasons why : [3]
(i) Sodium Chloride will conduct electricity only in fused or aqueous solution state.
(ii) In the electroplating of an article with silver, the electrolyte sodium argento- cyanide solution is preferred over silver nitrate solution.
(iii) Although copper is a good conductor of electricity, it is a non-electrolyte.
Answer:
(i) Sodium chloride is a solid, ionic compound, it has strong electrostatic forces of attraction. Only in the fused or aqueous solution, it forms ions which are capable of conducting electricity.
(ii) It is preferred over silver nitrate because the dissociation of AgNO₃ will be very fast and deposit will not be smooth and uniform.
(iii) An electrolyte must have free ions which act as charge carriers where as in copper the free electrons act as charge carriers.

Question 7.
(a) (i) Name the solution used to react the Bauxite as a first step in obtaining pure aluminium oxide, in the Baeyer’s process. [5]
(ii) Write the equation for the reaction where the aluminum oxide for the electrolytic extraction of aluminum is obtained by heating aluminum hydroxide.
(iii) Name the compound added to pure alumina to lower the fusion temperature during the electrolytic reduction of alumina.
(iv) Write the equation for the reaction that occurs at the cathode during the extraction of aluminium by electrolysis.
(v) Explain why it is preferable to use a number of graphite electrodes as anode instead of a single electrode, during the abvoe electrolysis.
Answer:
(i) Sodium hydroxide solution
(ii)

(iii) Cryolite (Na₃Al F₆) acts as a solvent and lower the fusion temperature from 2050°C to 950°C.
(iv) Cathode : (rich in electron)
Al³⁺ + 3e^– → Al
(v) It is preferable to use a number of graphite electrodes as anode because anode gets oxidised by the oxygen evolved.
Hence, if large number of electrodes are used it will keep the process continuous for a longer time.

(b) State what would you observe when : [2]
(i) Washing Soda Crystals are exposed to the atmosphere.
(ii) The salt ferric chloride is exposed to the atmosphere.
Answer:
(i) Na₂CO₃.10H₂O → Na₂CO₃.H₂O + 9H₂O
It will loose water of crystallisation and become a monohydrate. The appearance will be dull and flaky.
(ii). Ferric chloride is a deliquescent substance, thus it will absorb water from atmosphere and finally dissolve in that water forming a saturated solution.

(c) Identify the cations in each of the following case : [3]
(i) NaOH solution when added to the Solution (A) gives a reddish brown precipitate.
(ii) NH₄OH Solution when added to the Solution (B) gives white ppt. which does not dissolve in excess.
(iii) NaOH Solution when added to Solution (C) gives white ppt. which is insoluble in excess.
Answer:
(i) Ferric
(ii) Lead
(iii) Calcium

Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2013  is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2013 Solved

Time: 1½ hour
Maximum Marks: 80

General Instructions:

• Answer to this Paper must he written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question Paper.
• The time given at the head of this paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The intended marks for questions or parts of questions are given in brackets [ ].

Section I (40 Marks)
Attempt all questions from this Section.

Question 1.(a) From the list given below, select the word(s) required to correctly complete blanks (i) to (v) in the following passage. The words from the list are to be used only once. Write the answers as (a) (i), (ii), (iii) and so on. Do not copy the passage.
[ammonia, ammonium, carbonate, carbon dioxide, hydrogen, hydronium, hydroxide,precipitate, salt, water]:
(i) A solution M turns blue litmus red, so it must contain (i) ………………… ions; another solution O turns red litmus blue and hence, must contain (ii) …………………. ions.
(ii) When solutions M and O are mixed together, the products will be (iii) …………………. and (iv) ………………….
(iii) If a piece of magnesium was put into a solution M, (v) …………………. gas would be evolved. [5]
Answer:
(i) hydronium,
(ii) hydroxide
(iii) salt,
(iv) water
(v) hydrogen

(b) Identify the gas evolved in the following reactions when :
(i) sodium propionate is heated with soda lime.
(ii) potassium sulphite is treated with dilute hydrochloric acid.
(iii) sulphur is treated with concentrated nitric acid.
(iv) a few crystals of KNOa are heated in a hard glass test tube.
(v) concentrated hydrochloric acid is made to react with manganese dioxide. (5)
Answer:
(i) Ethane
(ii) Sulphur dioxide
(iii) Nitrogen dioxide
(iv) Oxygen
(v) Chlorine

(c) State one appropriate observation for each of the following:
(i) Concentrated sulphuric acid is added drop wise to a crystal of hydrated copper sulphate.
(ii) Copper sulphide is treated with dilute hydrochloric acid.
(iii) Excess of chlorine gas is reacted with ammonia gas.
(iv) A few drops of dilute hydrochloric acid are added to silver nitrate solution, followed by addition of ammonium hydroxide solution.
(v) Electricity is passed through molten lead bromide. (5)
Answer:
(i) The blue crystals (of CuSO₄.5H₂O) change to a white powder (of CuSO₄).
(ii) A gas having rotten egg smell (H₂S) is released which turns lead acetate paper black.
(iii) A yellow explosive liquid (nitrogen trichloride) is formed.
(iv) A curdy white precipitate (of AgCl) is formed which is insoluble in HNO₃ but soluble in NH₄OH.
(v) A silvery white metal (of Pb) is deposited at cathode.

(d) Give suitable chemical terms for the following :
(i) A bond formed by a shared pair of electrons with both electrons coming from the same atom.
(ii) A salt formed by incomplete neutralisation of an acid by a base.
(iii) A reaction in which hydrogen of an alkane is replaced by a halogen.
(iv) A definite number of water molecules bound to some salts.
(v) The process in which a substance absorbs moisture from the atmosphere air to become moist, and ultimately dissolves in the absorbed water.
Answer:
(i) Coordinate bond
(ii) Acidic salt
(iii) Subsitution reaction
(iv) Water of crystallisation
(v) Deliquescence

(e) Give a chemical test to distinguish between the following pairs of compounds : [5]
(i) Sodium chloride solution and sodium nitrate solution.
Answer:
Add AgNO₃ solution to both the solutions of salt in water.
NaCl solution – curdy white precipitates of AgCl are formed which are insoluble in HNO₃ but soluble in NH₄OH.
NaNO₃ solution – no reaction.

(ii) Hydrogen chloride gas and hydrogen sulphide gas.
Answer:
A rod dipped in NH₄OH is brought near gas jars containing HCl gas and H₂S gas respectively.
HCl gas – dense white fumes of NH₄Cl are seen.
H₂S gas – no reaction.

(iii) Ethene gas and ethane gas.
Answer:
Add a few drops of bromine solution in carbon tetrachloride to the given hydrocarbons.
Ethene gas-the reddish brown colour of bromine solution gets decolourized.
Ethane gas-no change in colour.

(iv) Calcium nitrate solution and zinc nitrate solution.
Answer:
Add NH₄OH to both the salt solutions.
Ca(NO₃)₂ – White ppts. of Ca(OH)₂ are seen.
Zn(NO₃)₂ – gelatinous white ppts. of Zn(OH)₂ are seen which dissolves in excess of NH₄OH.

(v) Carbon dioxide gas and sulphur dioxide gas.
Answer:
Pass both the gases through excess of limewater.
CO₂ gas-turns limewater milky, and even in excess of limewater, the milkiness remains.
SO₂ gas-turns limewater milky, but on passage through excess of limewater, milkiness disappears.

(f) Choose the most appropriate answer from the following options :
(i) Among the period 2 elements, the element which has high electron affinity is
(a) Lithium
(b) Carbon
(c) Chlorine
(d) Fluorine
Answer:
(d) Fluorine has highest electron affinity

(ii) Among the following compounds identify the compound that has all three bonds (ionic, covalent and coordinate bond).
(a) Ammonia
(b) Ammonium chloride
(c) Sodium hydroxide
(d) Calcium chloride
Answer:
(b) Ammonium chloride has all the three electronic bonds

(iii) Identify the statement that is incorrect about alkanes :
(a) They are hydrocarbons.
(b) There is single covalent bond between carbon and hydrogen
(c) They can undergo both substitution as well as addition reactions
(d) On complete combustion they produce carbon dioxide and water.
Answer:
(c) They can undergo both substitution as well as addition reactions.

(iv) Which of these will act as non-electrolyte ?
(a) Liquid carbon tetrachloride
(b) Acetic acid
(c) Sodium hydroxide aqueous solution acid,
(d) Potassium chloride aqu. solution.
Answer:
(a) Liquid carbon tetrachloride is non-electrolyte

(v) Which one of the following will not produce an acid when made to react with water ?
(a) Carbon monoxide
(b) Carbon dioxide
(c) Nitrogen dioxide
(d) Sulphuric trioxide.
Answer:
(a) Carbon monoxide gas

(vi) Identify the metallic oxide which is amphoteric in nature :
(a) Calcium oxide
(b) Barium oxide
(c) Zinc oxide
(d) Copper (II) oxide
Answer:
(c) Zinc oxide is an amphoteric oxide

(vii) In the given equation identify the role played by concentrated sulphuric acid
S + 2H₂SO₄ → 3 SO₂ + 2H₂O:
(a) Non-volatile acid
(b) Oxidising agent
(c)Dehydrating agent
(d) none of these
Answer:
(b) Concentrated sulphuric acid acts as oxidising agent

(viii) Nitrogen gas can be obtained by heating :
(a) Ammonium nitrate
(b) Ammonium nitrite
(c) Magnesium nitric
(d) Ammonium chloride
Answer:
(b) Ammonium nitrite

(ix) Which of the following is not a typical property of an ionic compound ?
(a) High melting point
(b) Conducts electricity in the molten and in the aqueous solution state
(c) They are insoluble in water
(d) They exist as oppositely charged ions even in the solid state.
Answer:
(c) Ionic compounds are generally insoluble in water

(x) The metals zinc and tin are present in the alloy: (10)
(a) Solder
(b) Brass
(c) Bronze
(d) Duralumin.
Ans.
(c) Bronze

(g) Solve the following :
(i) What volume of oxygen is required to burn completely 90 dm3 of butane under similar conditions of temperature and pressure ? 2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O
Answer:
2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O
2 vol. of C₄H₁₀ → 13 vol. of O₂
1 vol. of C₄H₁₀ → \(\frac{13}{2}\) vol. of O₂
90 dm³ of C₄H₁₀ → \(\frac{13}{2}\) × 90
⇒ 585 dm³ of O₂

(ii) The vapour density of a gas is 8. What would be the volume occupied by 24.0 g of the gas at STP ? (2)
Answer:
VD = 8
R.M.W. = 2 × VD ⇒ 2 × 8 ⇒ 16 g
∴ 16 g of gas ⇒ 22.4 l
1 g of gas ⇒ \(\frac{22.4}{16}\)
24 g of gas ⇒ \(\frac{22.4}{16}\) × 24
⇒ 33.6 l

(iii) A vessel contains X number of molecules of hydrogen gas at a certain temperature and pressure, flow many molecules of nitrogen gas would be present in the same vessel under the same conditions of temperature and pressure ? (1)
Answer:
No. of H₂ molecules in the vessel = X
∴ by Avogadro’s law, no. of N₂ molecules in the same vessel under similar conditions of temperature and pressure = X

Section – II (40 Marks)
Attempt any four questions from this Section

Question 2.
(a)

• In this table H does not represent hydrogen.
• Some elements arc given in their own symbol and position in the periodic table.
• While others are shown with a letter.

With reference to the table answer the following questions.
(i) Identify the most electronegative element. (1)
(ii) Identify the most reactive element of group 1. (1)
(iii) Identify the element from period 3 with least atomic size. (1)
(iv) How many valence electrons are present in Q ? (1)
(v) Which element from group 2 would have the least ionization energy ? (1)
(vi) Identify the noble gas of the fourth period. (1)
(vii) In the compound between A and H what type of bond would be formed and give the molecular formula for the same. (2)
Answer:
(i) J (fluorine)
(ii) R (potassium)
(iii) M (chlorine)
(iv) 5 valence e^–
(v) T (calcium)
(vi) Y (krypton)
(vii) ionic, (A₂H)

(b) Compare the compounds carbon tetrachloride and sodium chloride with regard to solubility in water and electrical conductivity. (2)
Answer:

	CCl4	NaCl
Solubility in water: Electrical conductivity:	Insoluble in water Bad conductor of electricity, molten or aqueous state.	Soluble in water Good conductor of electricity in

Question 3.
(a) Choosing the substances from the list given below, write balanced chemical equations for the reactions which would be used in the laboratory to obtain the following salts : [4]

Dilute Sulphuric acid	Copper	Copper (II) carbonate
	Iron	Sodium carbonate
	Sodium	Sodium chloride
		Zinc nitrate

(i) Sodium sulphate
(ii) Zinc carbonate
(iii) Copper (II) sulphate
(iv) Iron (II) sulphate.
Answer:
(i) 2NaCl + H₂SO₄ (dil.) → Na₂SO₄ + 2HCl
(ii) Zn(NO₃)₂ + Na₂CO₃ → ZnCO₃ + 2NaNO₃
(iii) CuCO₃ + H₂SO₄ (dil.) → CuSO₄ + H₂O + CO₂
(iv) Fe + H₂SO₄ (dil.) → FeSO₄ + H₂

(b) State two relevant observations for each of the following :
(i) Ammonium hydroxide solution is added to copper (II) nitrate solution in small quantities and then in excess.
(ii) Ammonium hydroxide solution is added to zinc nitrate solution in minimum quantities and then in excess.
(iii) Lead nitrate crystals are heated in a hard glass test tube. [6]
Answer:
(b) (i) (1) When NH₄OH is added in small quantity, pale blue ppt. (of Cu (OH)₂) are formed.
(2) When NH₄OH is added in excess, the ppt. dissolve to form a complex to give an inky blue solution.

(ii) (1) When NH₄OH is added in small quantity, gelatinous white ppt. (of Zn (OH)₂) are formed.
(2) When NH₄OH is added in excess, the ppt. dissolve to form a complex, to give clear solution.

(iii) (1) A yellow coloured compound (PbO) is formed which fuses with the walls of the test tube.
(2) A reddish brown gas (NO₂) is evolved.

Question 4.
(a) Copper sulphate solution is electrolysed using copper electrodes.
Study the diagram given below and answer the question that follows:

(i) Which electrode to your left or right is known as the oxidising electrode and why? (2)
Answer:
Left (anode ; + ve terminal of the battery). It is called the oxidising electrode as anions give their electrons to anode, and thus undergo oxidation.

(ii) Write the equation representing the reaction that occurs. (1)
Answer:
At cathode (-ve terminal of battery ; rich in e^–)
Cu²⁺ + 2e^– → Cu
At anode (+ ve terminal of battery ; deficient in e~)
Cu – 2e^– → Cu²⁺

(iii) State two appropriate observations for the above electrolysis reaction. (2)
Answer:
(1) Blue colour of CuSO₄ solution does riot fade.
(2) Anode withers aways. Loss in weight of anode is always equal to gain in weight of cathode.

(b)

	X	Y
Normal Electronic Configuration	2, 8, 7	2, 8, 2
Nature of oxide	Dissolves in water and turns blue litmus red	Very low solubility in water. Dissolves in hydrochloric acid
Tendency for oxidising and reducing reactions	Tends to oxidise elements and compounds	Tends to act as a reducing agent
Electrical and Thermal conductivity	Very poor electrical conductor; Poor thermal conductivity	Good Electrical conductor Good Thermal conductor
Tendency to form alloys and amalgums	No tendency to form alloys	Forms alloys

Using the information above, complete the following :
(i) ……………… is the metallic element.
(ii) Metal atoms tend to have a maximum of ……………… electrons in the outermost energy level.
(iii) Non-metallic elements tend to form ……………… oxides while metals tend to form ……………… oxides.
(iv) Non-metallic elements tend to be ……………… conductors of heat and electricity.
(v) Metals tend to ……………… electrons and act as ……………… agents in their reactions with elements and compounds. (5)
Answer:
(i) Y,
(ii) Three
(iii) acidic, basic
(iv) bad
(v) lose, reducing

Question 5.
a. Give balanced equations for each of the following : (4)
(i) Reduction of hot Copper (II) oxide to copper using ammonia gas.
Answer:
(i) 3CuO + 2NH₃ → 3Cu + 3H₂O + N₂

(ii) Oxidation of carbon with concentrated nitric acid.
Answer:
C + 4HN₃ → CO₂ + 2H₂O+ 4NO₂

(iii) Dehydration of concentrated sulphuric acid with sugar crystals
Answer:

(b) Copy and complete the following table relating to important industrial process:

Answer:

(c) The following questions relate to the extraction of aluminium by electrolysis :
(i) Name the other aluminium containing compound added to alumina and state its significance.
Answer:
Cryolite (Na₃AlF₆)

• It acts as a solvent.
• It lowers the fusion temperature from 2050°C to 950°C

(ii) Give the equation for the reaction that takes place at the cathode.
Answer:
At cathode (-ive terminal of battery ; rich in e^–)
Al⁺³ + 3e^– → Al

(iii) Explain why is it necessary to renew the anode periodically.
Answer:
At anode, O₂ is evolved, which reacts with carbon anode to form CO and futher forms CO₂.

Question 6.
(a) Give balanced equations for the laboratory preparations of the following organic compounds : (4)
(i) A saturated hydrocarbon from iodomethane.
Answer:

(ii) An unsaturated hydrocarbon from an alcohol.
Answer:

(iii) An unsaturated hydrocarbon from calcium carbide.
Answer:
CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂

(iv) An alcohol from ethyl bromide.
Answer:
C₂H₅Br + KOH → KBr + C₂H₅OH

(b) Give the structural formulae for the following : (3)
(i) An isomer of n-butane.
Answer:

(ii) 2-propanol.
Answer:

(iii) Diethyl ether.
Answer:
C₂H₅ – O – C₂H₅ (Diethyl ether)

(c) Give reasons for the following : [3]
(i) Methane does not undergo addition reactions, but ethene docs.
Answer:
Methane does not undergo addition reactions, but ethene does because methane is a saturated compound but ethene is an unsaturated hydrocarbon.

(ii) Gthync is more reactive than ethane.
Answer:
Ethyne is more reactive than ethane because ethyne has triple bond but ethane has single bond. Ethyne is unstable, so it reacts with other compounds in order to become stable.

(iii) Hydrocarbons arc excellent fuels.
Answer:
Hydrocarbons are excellent fuels because they are inflammable.

Question 7.
(a) O₂ is evolved by heating KClO₃ using MnO₂ as a catalyst
2KClO₃ → 2KCl + 3O₂
(i) Calculate the mass of KClO₃ required to produce 6.72 litre of 02 at STP. [atomic masses of K = 39, Cl = 35.5, O = 16] (2)
Answer:
To produce 67.2 L of O₂ → 225 g of KClO₃ is used
To produce 1 L of O₂ → \(\frac{225}{67.2}\) of KClO₃ is used
To produce 6.72 L of O₂ → \(\frac{225}{67.2} \times \frac{67.2}{100}\) × 10 ⇒ 22.5 g

(ii) Calculate the number of moles of oxygen present in the above volume and also the number of molecules. (2)
Answer:

(iii) Calculate the volume occupied by 0.01 mole of CO₂ at STP. (1)
Answer:
1 mole occupies → 22.4 L of volume of CO₂
0.01 mole occupies → \(\frac{224}{10} \times \frac{1}{100}=\frac{224}{1000}\) ⇒ 0.224 L.

(b) Identify the following substances which are underlined :
(i) An alkaline gas which produces dense white fumes when reacted with hydrogen chloride gas.
Answer:
Ammonia

(ii) An acid which is present in vinegar.
Answer:
Acetic acid

(iii) A gas which does not conduct electricity in the liquid state but conducts electricity when dissolved in water.
Answer:
Hydrogen chloride

(iv) A dilute mineral acid which forms a white precipitate when treated with barium chloride solution.
Answer:
Dilute sulphuric acid.

(v) The element which has the highest ionization potential.
Answer:
Fluorine.

Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2014 is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2014 Solved

Time : 2 hour
Maximum Marks: 40

General Instructions:

• Answers to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question Paper.
• The time given at the head of this paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The Intended marks for questions or parts of questions are given in brackets [ ].

SECTION -1 (40 MARKS)
(Attempt all questions from this Section)

Question 1.
(a) Choose the correct answer from the options given below: [10]
(i) Ionisation Potential increases over a period from left to right because the:
(A) Atomic radius increases and nuclear charge increases
(B) Atomic radius decreases and nuclear charge decreases
(C) Atomic radius increases and nuclear charge decreases
(D) Atomic radius decreases and nuclear charge increases.
Answer:
(D) Atomic radius decreases and nuclear charge increases.

(ii) A compound X consists of only molecules. Hence X will have:
(A) A crystalline hard structure
(B) A low melting point and low boiling point
(C) An ionic bond
(D) A strong force of attraction between its molecules.
Answer:
(B) A low melting point and low boiling point

(iii) When fused lead bromide is electrolysed we observe:
(A) a silver grey deposit at anode and a reddish brown deposit at cathode
(B) a silver grey deposit at cathode and a reddish brown deposit at anode
(C) a silver grey deposit at cathode and reddish brown fumes at anode
(D) silver grey fumes at anode and reddish brown fumes at cathode.
Answer:
(C) a silver grey deposit at cathode and reddish brown fumes at anode

(iv) The main ore used for the extraction of iron is:
(A) Haematite
(B) Calamine
(C) Bauxite
(D) Cryolite
Answer:
(C) Bauxite

(v) Heating an ore in a limited supply of air or in the absence of air at a temperature just below its melting point is known as:
(A) smelting
(B) ore dressing
(C) calcination
(D) bessemerisation
Answer:
(C) calcination

(vi) If an element A belongs to Period 3 and Group II then it will have,
(A) 3 shells and 2 valence electrons
(B) 2 shells and 3 valence electrons
(C) 3 shells and 3 valence electrons
(D) 2 shells and 2 valence electrons
Answer:
(B) 2 shells and 3 valence electrons

(vii) The molecule containing a triple co-valent bond is:
(A) ammonia
(B) methane
(C) water
(D) nitrogen
Answer:
(D) nitrogen

(viii) The electrolyte used for electroplating an article with silver is:
(A) silver nitrate solution
(B) silver cyanide solution
(C) sodium argentocyanide solution
(D) nickel sulphate solution
Answer:
(C) sodium argentocyanide solution

(ix) Aluminium powder is used in thermite welding because,
(A) it is a strong reducing agent
(B) it is a strong oxidising agent
(C) it is corrosion resistant
(D) it is a good conductor of heat.
Answer:
(A) it is a strong reducing agent

(x) The I.U.P.A.C. name of acetylene is,
(A) propane
(B) propyne
(C) ethene
(D) ethyne.
Answer:
(D) ethyne.

(b) Fill in the blanks from the choices given within brackets: [5]
(i) The basicity of Acetic Acid is . (3, 1, 4)
(ii) The compound formed when ethanol reacts with sodium is (sodium ethanoate, sodium ethoxide, sodium propanoate)
(iii) Quicklime Is not used to dry HCl gas because (CaO is alkaline, CaO is acidic, CaO is neutral)
(iv) Ammonia gas is collected by (an upward displacement of air, a downward displacement of water, a downward displacement of air)
(v) Cold, dilute nitric acid reacts with copper to form dioxide, nitric oxide).
Answer:
(i) 1
(ii) Sodium ethoxide
(iii) CaO is alkaline
(iv) Downward displacement of air.
(v) Nitric oxide.

(c) Give one word or phrase for the following:
(i) The ratio of the mass of a certain volume of gas to the mass of an equal volume of hydrogen under the same conditions of temperature and pressure.
(ii) Formation of ions from molecules.
(iii) Electrolytic deposition of a superior metal on a baser metal.
(iv) Hydrocarbons containing

functional group.
(v) The amount of energy released when an atom in the gaseous state accepts an electron to form an anion. [5]
Answer:
(i) Vapour density
(ii) Ionisation
(iii) Electroplating
(iv) Ketones
(v) Electron affinity

(d) Match the options A to E with the statements (i) to (v): [5]

A. alkynes	(i) No. of molecules In 22.4 dm3 of carbon dioxide at s.t.p.
B. alkane	(ii) An element with electronic configuration 2, 8, 8,3
C. iron	(iii) CnH2n+2
D. 6.023 × 1023	(iv) CnH2n-2
E. metal	(v) The metal that forms two types of ions

Answer:

A. alkynes	(iv) CnH2n-2
B. alkane	(iii) CnH2n+2
C. iron	(v) The metal that forms two types of ions
D. 6.023 × 1023	(i) No. of molecules In 22.4 dm3 of carbon dioxide at s.t.p.
E. metal	(ii) An element with electronic configuration 2, 8, 8,3

(e) Write balanced equations for the following:
(i) Action of heat on a mixture of copper and concentrated nitric acid.
(ii) Action of warm water on magnesium nitride.
(iii) Action of concentrated sulphuric acid on carbon.
(iv) Action of dilute hydrochloric acid on sodium sulphide.
(v) Preparation of ethane from sodium propionate. [5]
Answer:
(i)

(ii) Mg₃N₂ + 6H₂O → 3Mg(OH)₂ + 2NH₃↑
(iii) C + 2H₂SO₄ → CO₂↑ + 2H₂O + 2SO₂↑
(iv) Action of dilute hydrochloric acid on sodium suiphide.
Na₂S + 2HCl → 2NaCl + H₂S
(v)

(f) Distinguish between the following pairs of compounds using the test given within brackets:
(i) Iron (II) sulphate and iron (III) sulphate (using ammonium hydroxide)
(ii) A lead salt and a zinc salt (using excess ammonium hydroxide)
(iii) Sodium nitrate and sodium sulphite (using dilute sulphuric acid)
(iv) Dilute sulphuric acid and dilute hydrochloric acid (using barium chloride solution)
(v) Ethane and ethene (using alkaline potassium permanganate solution) [5]
Answer:

(i) Iron (II) sulphate FeSO4 + 2NH4OH →  Fe(OH)2 ↓ +(NH4)2SO4 Dirty green ppts. of Fe(OH)2 are formed.	Iron (III) sulphate Fe2(SO4)3+ 3NH4OH → Fe(OH) 3 ↓ + 3NH4C1 Reddish brown ppts. of Fe(OH)3 are formed.
(ii) A lead salt Pb(NO3)2 + 2NH4OH → Pb(OH)2 ↓ + 2NH4NO3 It is insoluble in excess and forms chalky white precipitates.	A zinc salt ZnSO4 + 2NH4OH → Zn(OH)2 ↓ +(NH4)2SO4 Zn(OH)2 + (NH4)2SO4 + 2NH4OH → [Zn(NH3)4]SO4 + 4H2O It is soluble in excess and forms gelatinous white precipitates.
(iii). NaN03 (Sodium nitrate) 2NaNO3 + H2SO4 → Na2SO4 + 2HNO3	Na2SO3 (Sodium sulphite) Na2SO3 + H2SO4 → Na2SO4+ H2O + SO2
(iv) Dilute H2SO4 BaCl2 + H2SO4      Ba(SO4)2 ↓ + 2HCl If forms white ppt. of Ba(S04)2.	Dilute HCl BaCl2 + HCl → No reaction No precipitates are formed.
(v) Ethane The pink colour of KMnO4 remains the same.	Ethene The pink colour of KMnO4 is discharged.

(g) (i) Oxygen oxidises ethyne to carbon dioxide and water as shown by the equation:
2C₂H₂ + 5o₂ → 4CO₂ + 2H₂O
What volume of ethyne gas at s.t.p. is required to produce 8.4 dm3 of carbon dioxide at s.t.p.? [H = 1, C = 12, O = 16]
Answer:

(ii) A compound made up of two elements X and Y has an empirical formula X,Y. If the atomic weight of X is 10 and that of Y is 5 and the compound has a vapour density 25, find its molecular formula. [5]
Answer:
Empirical formula = X2Y
Atomic weight of X = 10
Atomic weight of Y = 5
V.D. of compound = 25
M.F. = ?
Molecular mass = 2 × V.D.
= 2 × 25 = 50
Empirical mass = 2 × 10 + 5
= 20 + 5
= 25
Molecular mass
n = \(\frac{\text { Molecular mass }}{\text { Empirical mass }}\)
= \(\frac{50}{25}\)
= 2
Molecular formula = (E.F.)₂
= (X₂Y)₂
= X₄Y₂

SECTION – II (40 MARKS)
(Attempt any four questions from this Section)

Question 2.
(a) State your observation in each of the following cases:
(i) When dilute hydrochloric acid is added to sodium carbonate crystals.
(ii) When excess sodium hydroxide is added to calcium nitrate solution.
(iii) At the cathode when acidified aqueous copper sulphate solution is electrolyzed with copper electrodes.
(iv) When calcium hydroxide is heated with ammonium chloride crystals.
(v) When moist starch iodide paper is introduced into chlorine gas. [5]
Answer:
(i) Brisk effervescence of a gas which turns lime water milky (CO₂) is evolved.
(ii) White precipitates are formed that are sparingly soluble in water.
(iii) Reddish metal (copper) is deposited on cathode.
(iv) An ammonical smelling gas (NH₃) is released.
(v) It turns moist starch iodide paper blue black.

(b) Study the figure given below and answer the questions that follow:

(i) Identify the gas Y.
(ii) What property of gas Y does this experiment demonstrate?
(iii) Name another gas which has the same property and can be demonstrated through this experiment. [3]
Answer:
(i) Hydrogen chloride.
(ii) High solubility of hydrogen chloride.
(iii) Ammonia.

(c) (i) Name the other ion formed when ammonia dissolves in water.
(ii) Give one test that can be used to detect the presence of the ion produced. [2]
Answer:
(i) Hydroxyl [NH₃ + H₂O ⇌ NH₄OH → NH₄⁺ + OH^–]

(ii) It turns red litmus blue.

Question 3.
(a) State the conditions required for the following reactions to take place:
(i) Catalytic hydrogenation of ethyne.
(ii) Preparation of ethyne from ethylene dibromide.
(iii) Catalytic oxidation of ammonia to nitric oxide.
(iv) Any two conditions for the conversion of sulphur dioxide to sulphur trioxide. [5]
Answer:
(i) Nickel at 200°C
(ii) Alcoholic KOH (KOH alc.)
(iii) Platinum at 800°C
(iv) U₂O₅ as catalyst and K₂O as a promoter.
Temperature → 450 – 500°C

(b) State the main components of the following alloys:
(i) Brass.
(ii) Duralumin.
(iii) Bronze, [3]
Answer:
(i) Copper and zinc
(ii) Aluminium, copper, magnesium and manganese
(iii) Copper, zinc and tin

(c) Give balanced equations for the following:
(i) Laboratory preparation of nitric acid.
(ii) Preparation of ethanol from monochloroethane and aq. sodium hydroxide. [2]
Answer:

Question 4.
(a) Give the structural formula of the following:
(i) ethanol.
(ii) 1-propanal.
(iii) ethanoic acid.
(iv) 1,2, dichloroethane. [4]
Answer:
Give the structural formula:

(b) Draw the structure of the stable positive ion formed when an acid dissolves in water. [2]
Answer:

(c) State the inference drawn from the following observations:
(i) On carrying out the flame test with a salt P a brick red flame was obtained. What is the cation in P?
(ii) A gas Q turns moist lead acetate paper silvery black. Identify the gas Q.
(iii) pH of liquid R is 10. What kind of substance is R?
(iv) Salt S is prepared by reacting dilute sulphuric acid with copper oxide. Identify S.
Answer:
(i) Cation in P is Ca²⁺.
(ii) Hydrogen sulphide
(iii) R is a basic substance as its pH is greater
(iv) Copper sulphate (CuSO₄) greater than 7

Question 5.
(a) Name the following:
(i) The property possessed by metals by which they can be beaten into sheets.
(ii) A compound added to lower the fusion temperature of electrolytic bath in the extraction of aluminium.
(iii) The ore of zinc containing its sulphide. [3]
Answer:
(i) Malleability
(ii) Cryolite
(iii) Zinc Blende.

(b) Give one equation each to show the following properties of sulphuric acid:
(i) Dehydrating property.
(ii) Acidic nature.
(iii) As a non-volatile acid. [3]
Answer:
(i)
im – 6

(ii) It reacts with alkalies and shows neutralisation reaction.
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O.

(iii)
im – 7

(c) Give balanced chemical equations to prepare the following salts:
(i) Lead sulphate from lead carbonate.
(ii) Sodium sulphate using dilute sulphuric acid.
(iii) Copper chloride using copper carbonate. [4]
Answer:
(i)

Note: To convert insoluble salt to insoluble salt, two step reaction is needed i.e., to convert insoluble into soluble and then soluble to insoluble.

(ii)

(iii) CuCO₃ + 2HCl → CuCl₂ + H₂O + CO₂

Question 6.
(a) (i) State Avogadro’s Law.
(ii) A cylinder contains 68g of ammonia gas at s.t.p.
1. What is the volume occupied by this gas?
2. How many moles of ammonia are present in the cylinder?
3. How many molecules of ammonia are present in the cylinder? [N-14, H-1] [4]
Answer:
(i) Avogadro’s Law states that equal volumes of all gases under similar conditions of temperature and pressure contain the same no. of molecules.

(ii) Cylinder contains ammonia = 68 g
(1) Molecular mass of ammonia = [NH₃] = 14 + 3 = 17g
17 g of ammonia at s.t.p. occupies volume = 22.4 L
1 g of ammonia at s.t.p. occupies volume 22.4
= \(\frac{22.4}{17}\) L
68 g of ammonia at s.t.p. occupies volume = \(\frac{22.4}{17}\) × 68 = 89.6 L

(2) 17 g of ammonia = 1 mole
1 g of ammonia = \(\frac{1}{17}\) mole
68 g of ammonia = \(\frac{1}{17}\) × 68 mole = 4 mole of ammonia

(3) 1 mole contains = 6.022 × 10²³ molecules
4 mole contains = 4 × 6.022 × 10²³
= 24.088 × 10²³ molecules

(b) (i) Why do covalent compounds exist as gases, liquids or soft solids?
(ii) Which electrode: anode or cathode is the oxidising electrode? Why? [3]
Answer:
(i) Covalent compounds are bound by weak van der Waal forces of attraction so the molecules of the compound are loosely bound, thus due to weak forces they exist as gases, liquids or soft solids.
(ii) Anode is oxidising anode because loss of electrons takes place at anode.

(c) Name the kind of particles present in:
(i) Sodium Hydroxide solution.
(ii) Carbonic acid.
(iii) Sugar solution. [3]
Answer:
(i) Ions
(ii) Ions as well as molecules
(iii) Molecules

Question 7.
(a) An element Z has atomic number 16. Answer the following questions on Z:
(i) State the period and group to which Z belongs.
(ii) Is Z a metal or a non-metal?
(iii) State the formula between Z and Hydrogen.
(iv) What kind of a compound is this? [4]
Answer:
(i)

It is in 3^rd period and 16^th group.

(ii) Non-metal

(iii)

(iv) Covalent compound

(b) M is a metal above hydrogen in the activity series and its oxide has the formula M20. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity. In the above context answer the following:
(i) What kind of combination exists between M and O?
(ii) How many electrons are there in the outermost shell of M?
(iii) Name the group of which M belongs.
(iv) State the reaction taking place at the cathode.
(v) Name the product at the anode. [5]
Answer:
(i) Electrovalent combination

(ii) 1 electron is present in M

(iii) Alkali metals

(iv) M₂O → 2M⁺ + O^2- at cathode,
M⁺ + 1e^– → M

(v) At anode
O^2- – 2e^– → O
[O] + [O] → O₂↑

Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2012 is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2012 Solved

Time: 1½ hour
Maximum Marks: 40

General Instructions:

• Answer to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question Paper.
• The time given at the head of this paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The intended marks for questions or parts of questions are given in brackets [ ].

SECTION -1 (40 MARKS)
(Attempt all questions from this Section)

Question 1.
(a) Name the gas in each of the following :
(i) The gas evolved on reaction of Aluminium with boiling concentrated caustic alkali solution.
(ii) The gas produced when excess ammonia reacts with chlorine.
(iii) A gas which turns acidified potassium dichromate clear green.
(iv) The gas produced when copper reacts with concentrated nitric acid.
(v) The gas produced on reaction of dilute sulphuric acid with a metallic sulphide. [5]
Answer:
(i) Hydrogen
(ii) Nitrogen
(iii) Sulphur dioxide
(iv) Nitrogen dioxide
(v) Hydrogen sulphide

(b) State one observation for each of the following :
(i) Excess ammonium hydroxide solution is added to lead nitrate solution.
(ii) Bromine vapours are passed into a solution of ethyne in carbon tetrachloride.
(iii) A zinc granule is added to copper sulphate solution.
(iv) Zinc nitrate crystals are strongly heated.
(v) Sodium hydroxide solution is added to ferric chloride solution at first a little and then in excess. [5]
Answer:
(i) A white ppt. of Pb(OH)₂ is formed which is insoluble in excess of NH₄OH.
(ii) The reddish brown coloured gas (Br₂) gets decolorised.
(iii) A gelatinous white ppt. of (ZnSO₄) is formed and the blue coloured solution gets decolorised due to its formation.
(iv) (ZnO). A ppt. is formed which is yellow when hot and white when cold.
(NO₂). A reddish brown gas is liberated which has a pungent, irritating odour and turns potassium iodide paper brown.
(O₂) A colourless, odourless gas is liberated which rekindles a glowing splinter.
(v) A reddish brown ppt [Fe(OH)₃] is formed which is insoluble in excess of NaOH.

(c) Some word/words are missing in the following statements. You are required to rewrite the statements in the correct form using the appropraite word/words :
(i) Ethyl alcohol is dehydrated by sulphuric acid at a temperature of about 170°C.
(ii) Aqua regia contains one part by volume of nitric acid and three parts by volume of hydrochloric acid.
(iii) Magnesium nitride reacts with water to liberate ammonia.
(iv) Cations migrate during electrolysis.
(v) Magnesium reacts with nitric acid to liberate hydrogen gas. [5]
Answer:
(i) Ethyl alcohol is dehydrated by concentrated sulphuric acid at a temperature of about 170°C.
(ii) Aqua regia contains one part by volume of cone, nitric acid and three parts by volume of cone, hydrochloric acid.
(iii) Magnesium nitride reacts with water to liberate ammonia and magnesium hydroxide.
(iv) Cations migrate towards cathode during electrolysis.
(v) Magnesium reacts with very dilute nitric acid (1%) to liberate hydrogen gas.

(d) Choose the correct answer from the options given below :
(i) An element in period-3 whose electron affinity is zero.
(A) Neon
(B) Sulphur
(C) Sodium
(D) Argon
Answer:
(D) Argon

(ii) An alkaline earth metal.
(A) Potassium
(B) Calcium
(C) Lead
(D) Copper
Answer:
(B) Calcium

(iii) The vapour density of carbon dioxide |C = 12, 0 = 16|
(A) 32
(B) 16
(C) 44
(D) 22
Answer:
(D) 22

(iv) Identify the weak electrolyte from the following :
(A) Sodium Chloride solution
(B) Dilute Hydrochloric acid
(C) Dilute Sulphuric acid
(D) Aqueous acetic acid.
Answer:
(D) Aqueous acetic acid.

(v) Which of the following metallic oxides cannot be reduced by normal reducing agents ?
(A) Magnesium oxide
(B) Copper(II) oxide
(C) Zinc oxide
(D) Iron(III) oxide [5]
Answer:
(A) Magnesium oxide

(e) Match the following : [5]

Column A	Column B
1. Acid salt	A. Ferrous ammonium sulphate
2. Double salt	B. Contains only ions
3. Ammonium hydroxide solution	C. Sodium hydrogen sulphate
4. Dilute hydrochloric acid	D. Contains only molecules
5. Carbon tetrachloride	E. Contains ions and molecules

Answer:

Column A	Column B
1. Acid salt	C. Sodium hydrogen sulphate
2. Double salt	A. Ferrous ammonium sulphate
3. Ammonium hydroxide solution	E. Contains ions and molecules
4. Dilute hydrochloric acid	B. Contains only ions
5. Carbon tetrachloride	D. Contains only molecules

(f) Give the structural formula for the following :
(i) Mcthanoic acid
(ii) Ethanal
(iii) Ethyne
(iv) Acetone
(v) 2-methyl propane. [5]
Answer:

(g) Concentrated nitric acid oxidises phosphorus to phosphoric acid according to the following equation :

If 9.3g of phosphorus was used in the reaction, calculate :
(i) Number of moles of phosphorus taken. [1]
(ii) The mass of phosphoric acid formed. [2]
(iii) The volume of nitrogen dioxide produced at STP.
[H = 1, N = 14, P = 31, O = 16] [2]
Answer:
Given, P + 5HNO₃ (conc.) → H₃PO₄ + H₂O + 5NO₂

(i) No. of moles of phosphorus taken
= \(\frac{9.3}{31}\) = \(\frac{93}{31 \times 10}\) = 0.3 mole

(ii) 31 g of Pgives 3(1) + 31 + 4 (16)g of H₃PO₄
3 + 31 + 64 = 98 g of H₃PO₄
9.3 g of P gives \(\frac{98}{31} \times \frac{93}{10}=\frac{9114}{310}\)g
= 29.4 g of H₂PO₄

(iii) 31 g of P gives 5 vol of NO₂
9.3 g of P gives \(\frac{5}{31} \times \frac{93}{10}\) = \(\frac{465}{310}\) × 22.4
= 33.6 L of NO₂

(h) Give reasons for the following :
(i) Iron is rendered passive with fuming nitric acid.
(ii) An aqueous solution of sodium chloride conducts electricity.
(iii) Ionisation potential of the element increases across a period.
(iv) Alkali metals are good reducing agents.
(v) Hydrogen chloride gas cannot be dried over quick lime.
Answer:
(i) Iron is rendered passive with fuming HNO₃ because of formation of reddish brown layer of iron oxide which prevents its further reaction with the acid.

(ii) An aqueous solution of sodium chloride contains electricity because water is polar solvent and has high dielectric constant which leads to formation of sodium and chloride ions which conduct electricity.

(iii) Ionisation potential of an element is the amount of energy required to remove one or more electrons from the outermost shell of an isolated gaseous atom.
Across a period, the atomic radii decreases due to increase in nuclear charge due to addition of electrons which results in greater attraction of valence shell electrons. Hence, I.P. increases.

(iv) Alkali metals are good reducing agents because alkali metals have one valence electron which they lose to attain stability. Hence, they themselves undergo oxidation causing reduction of others and are good reducing agents.

(v) Hydrogen chloride gas cannot be dried over quicklime because quicklime reacts with it as per the following reaction :
CaO + 2HCl → CaCl₂ + H₂O

SECTION – II (40 MARKS)
(Attempt any four questions from this Section)

Question 2.
(a) Some properties of sulphuric acid are listed below. Choose the role played by sulphuric acid as A, B, C, or D which is responsible for the reactions (i) to (v).
Some role/s may be repeated.
A. Dilute acid
B. Dehydrating agent
C. Non-volatile acid
D. Oxidising agent

Answer:
(i) B (Dehydrating agent)
(ii) D (Oxidising agent)
(iii) C (Non-volatile acid)
(iv) A (Dilute acid)
(v) D (Oxidising agent)

(b) Give balanced equations for the following reactions :
(i) Dilute nitric acid and Copper carbonate.
(ii) Concentrated hydrochloric acid and Potassium permanganate solution.
(iii) Ammonia and Oxygen in the presence of a catalyst.
(iv) Silver nitrate solution and Sodium chloride solution.
(v) Zinc sulphide and Dilute sulphuric acid. [5]
Answer:

Question 3.
(a) Select the correct answer from the list given in brackets :
(i) An aqueous electrolyte consists of the ions mentioned in the list, the ion which could be discharged most readily during electrolysis. |Fe²⁺, Cu²⁺, Pb²⁺, H⁺|.
(ii) The metallic electrode which does not take part in an electrolytic reaction.
[Cu, Ag, Pt, Ni|.
(iii) The ion which is discharged at the anode during the electrolysis of copper sulphate solutions using copper electrodes as anode and cathode. [Cu²⁺, OH^–, SC^^2-, H⁺|.
(iv) When dilute sodium chloride is electrolysed using graphite electrodes, the cation is discharged at the cathode most readily. [Na⁺, OH^–, H⁺, Cl |.
(v) During silver plating of an article using potassium argentocyanide as an electrolyte, the anode material should be [Cu, Ag, Pt, Fe]. [5]
Answer:
(i) Cu²⁺
(ii) Pt
(iii) Cu²⁺
(iv) H⁺
(v) Ag

(b) Match the properties and uses of alloys in List 1 with the appropriate answer from List 2.

List 1	List 2
1. The alloy contains Cu and Zn, is hard, silvery and is used in decorative articles.	A. Duralumin
2. It is stronger than Aluminium, light and is used in making light tools.	B. Brass
3. It is lustrous, hard, corrosion resistant and used in surgical instruments.	C. Bronze
4. Tin lowers the melting point of the alloy and is used for soldering purpose.	D. Stainless stell
5. The alloy is hard, brittle, takes up polish and is used for making statues.	E. Solder

Answer:

List 1	List 2
1. The alloy contains Cu and Zn, is hard, silvery and is used in decorative articles.	B. Brass
2. It is stronger than Aluminium, light and is used in making light tools.	A. Duralumin
3.  It is lustrous, hard, corrosior. resistant and used in surgical instruments.	D. Stainless steel
4.  Tin lowers the melting point of the alloy and is used for soldering purpose.	E. Solder
5. The alloy is hard, brittle, takes up	C. Bronze

Question 4.
polish and is used for making statues.
(a) Identify the anion present in the following compounds :
(i) Compound X on heating with copper turnings and concentrated sulphuric acid liberates a reddish brown gas.
(ii) When a solution of compound Y is treated with silver nitrate solution a white precipitate is obtained which is soluble in excess of ammonium hydroxide solution.
(iii) Compound Z which on reacting with dilute sulphuric acid liberates a gas which turns lime waer milky, but the gas has no effect on acidified potassium dichromate solution.
(iv) Compound L on reacting with Barium chloride solution gives a white precipitate insoluble in dilute hydrochloric acid or dilute nitric acid. [4]
Answer:
(i) Nitrate
(ii) Chloride
(iii) Carbonate
(iv) sulphate

(b) State one chemical test between each of the following pairs :
(i) Sodium carbonate and Sodium sulphite
(ii) Ferrous nitrate and Lead nitrate
(iii) Manganese dioxide and Copper(II) oxide [3]
Answer:
(i) Sodium carbonate and Sodium sulphate :
Add HCl (dil.) to both the compounds and pass the gas liberated through acidified potassium dichromate solution.
Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂↑
(No reaction in potassium dichromate solution)
Na₂SO₃ + 2HCl → 2NaCl + H₂O + SO₂↑
(Gas liberated will turn potassium dichromate solution green)

(ii) Ferrous nitrate and Lead nitrate :
When ammonium hydroxide is added to both the solution, the following reactions take place.

Thus, ferrous nitrate will give dirty green precipitates whereas lead nitrate will give chalky white precipitates.

(iii) Manganese dioixde and Copper (II) oxide :
To both the compounds add conc. HCl and heat, the following observations helps:

(c) Draw an electron dot diagram to show the structure of hydronium ion. State the type of bonding present in it. [3]
Answer:
Structure of hydronium ion:

Question 5.
(a) (i) 67.2 litres of hydrogen combines with 44.8 litres of nitrogen to form ammonia under specific conditions as :
N₂(g) + 3H₂(g) → 2NH₃(g)
Calculate the volume of ammonia produced. What is the other substance, if any, that remains in the resultant mixture? |2|
(ii) The mass of 5.6 dm3 of a certain gas at STP is 12.0 g. Calculate the relative molecular mass of the gas. [2]
(iii) Find the total percentage of Magnesium in magnesium nitrate crystals, Mg(NO₃)₂.6H₂O.
[Mg = 24; N = 14; O = 16 and H = 1| [2]
Answer:
(i) N₂(g) + 3H₂(g) → 2NH₃ ? (vol)
22.4 L of N₂ gives 3 × 22.4 L of H₂
44.8 L of N₂ gives = \(\frac{3 \times 22.4}{22.4}\) × 44.8 = 134.4 L of H₂
22.4 L of N₂ gives 2 × 22.4 L of NH₃,
44.8 L of N, gives \(\frac{2 \times 22.4}{22.4}\) × 44.8 = 89.6 L of NH₃

(ii) 1 dm³ = 1 L
5.6 dm³ = 5.6 L
5.6 L of gas has mass 12 g
22.4 L of gas has mass \(\frac{12}{56} \times \frac{224}{10}\) × 10 = 48 g

(iii) RMM of Mg(NO₃)₂.6H₂O
= 24 + 14(2) + 16(6) + 6(2)(1) + 6(16)
= (24 + 28 + 96) + 12 + 96 = 148 + 108 = 256 g
% of Mg \(\frac{24}{256}\) × 100 = \(\frac{25 \times 3}{8}=\frac{75}{8}\) = 9.375%

(b) Refer to the flow chart diagram below and give balanced equations with conditions, if any, for the following conversions A to D.

Answer:
A.

B. Fe + 2HCl → FeCl₂ + H₂↑
C. NH₃ + HCl → NH₄Cl
D. Pb(NO₃)₂ + 2HCl → PbCl₂ + 2HNO₃

Question 6.
(a) Name the following metals :
(i) A metal present in cryolite other than sodium.
(ii) A metal which is unaffected by dilute or concentrated acids.
(iii) A metal present in period 3, group 1 of the periodic table. [3]
Answer:
(i) Aluminium
(ii) Gold
(iii) Sodium

(b) The following questions are relevant to the extraction of Aluminium :
(i) State the reason for addition of caustic alkali to bauxite ore during purification of bauxite.
(ii) Give a balanced chemical equation for the above reaction.
(iii) Along with cryolite and alumina, another substance is added to the electrolyte mixture. Name the substance and give one reason for the addition. [3]
Answer:
(i) Caustic alkali is added to bauxite ore during purification of bauxite because it reacts with bauxite to form soluble sodium meta aluminate and the impurities can be filtered off. The filtered solution can be then processed to get pure bauxite.

(ii)

(iii) Fluorspar is added to the electrolyte mixture is addition to cryolite and alumina.
Reason: It acts as a solvent for the electrolytic mixture and also increases its conductivity.

(c) The following questions are based on the preparation of ammonia gas in the laboratory:
(i) Explain why ammonium nitrate is not used in the preparation of ammonia.
(ii) Name the compound normally used as a drying agent during the process.
(iii) How is ammonia gas collected ?
(iv) Explain why it is not collected over water. [4]
Answer:
(i) Ammonium nitrate is not used in the preparation of ammonia because:

• It is explosive in nature.
• It decomposes giving nitrous oxide and water vapour.

(ii) Quicklime (CaO) is used as a drying agent during the process.

(iii) NH₃ gas is collected by downward displacement of air because :

• It is lighter than air.
• It is extremely soluble in water.

(iv) It is not collected over water because it is highly soluble in water.

Question 7.
(a) From the following organic compounds given below, choose one compound in each case which relates to the description (i) to (iv) :
(Ethyne, ethanol, acetic acid, cthene, methane)
(i) An unsaturated hydrocarbon used for welding purposes.
(ii) An organic compound whose functional group is carboxyl.
(iii) A hydrocarbon which on catalytic hydrogen nation gives a saturated hydrocarbon.
(iv) An organic compound used as a thermometric liquid. [4]
Answer:
(i) Ethyne
(ii) Acetic acid
(iii) Ethene
(iv) Ethanol

(b) (i) Why is pure acetic acid known as glacial acetic acid ?
(ii) Give a chemical equation for the reaction between ethyl alcohol and acetic acid. [2]
Answer:
(i) Pure acetic acid is called glacial acetic acid because at a temperature below 16.5°C is solidified as icy mass which floats at the surface of acetic acid as a glacier.
(ii)

(c) There are three elements E, F, G with atomic numbers 19, 8 and 17 respectively.
(i) Classify the elements as metals and non-metals. [3]
(ii) Give the molecular formula of the compound formed between E and G and state the type of chemical bond in this compound. [1]
Answer:
(i)

(ii)

Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2022 Semester 2 is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2022 Solved Semester 2

Time: 1½ hour
Maximum Marks: 40

General Instructions:

• Answers to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 10 minutes.
• This time is to be spent in reading the question paper.
• The time given at the head of this Paper is the time allowed for writing the answers.
• Attempt all questions from Section A and any three questions from Section B.
• The marks intended for questions are given in brackets [].

Section – A
(Attempt all questions)

Question 1.
Choose the correct answers to the questions from the given options. (Do not copy the question. Write the correct answer only.) [10]
(i) The ore of Aluminium is :
(a) Calamine
(b) Haematite
(c) Magnetite
(d) Cryolite
Answer:
(d) Cryolite (Na₃AlF₆)

(ii) Hydrogen chloride gas is not collected over water, as :
(a) It is highly soluble in water.
(b) It is less soluble in water.
(c) It is lighter than air.
(d) It is heavier than air.
Answer:
(a) Hydrogen chloride gas is highly soluble in water

(iii) An aqueous solution of ammonia is :
(a) Neutral
(b) Acidic
(c) Basic
(d) Amphoteric
Answer:
(c) NH₃ + H₂O ⇌ NH₄OH (Basic solution)

(iv) The acid which is least volatile is :
(d) Hydrochloric acid
(b) Nitric acid
(c) Dilute sulphuric acid
(d) Concentrated sulphuric acid
Answer:
(d) Conc. sulphuric acid is oily viscous liquid acid, which is least volatile.

(v) The gas formed, when calcium bisulphite reacts with dilute HNO₃:
(a) Sulphur trioxide
(b) Hydrogen
(c) Sulphur dioxide
(d) Hydrogen sulphide
Answer:
(c) Ca(HSO₃)₂ + 2HNO₃ → Ca(NO₃)₂ + 2H₂O + 2SO₂↑

(vi) The 1UPAC name of formic acid :
(a) Propanoic acid
(b) Methanoic acid
(c) Ethanoic acid
(d) Butanoic acid
Answer:
(b) HCOOH
Methanoic acid

(vii) The metallic oxide which when reacts with HCl forms salt and water :
(a) Carbon monoxide
(b) Nitrous oxide
(c) Ammonium hydroxide
(d) Sodium oxide
Answer:
(d)

(viii) Vanadium pentoxide is used as a catalyst in the preparation of:
(a) Nitrogen gas
(b) Nitrogen dioxide gas
(c) Sulphur trioxide gas
(d) Carbon dioxide gas
Answer:
(c) Vanadium pentoxide (V₂O₅) act as a catalyst in Contact process. It is a process used to prepare sulphur trioxide.

(ix) The Catalyst used for the conversion hydroxide of Ethene to Ethane:
(a) Iron
(b) Nickel
(c) Cobalt
(d) Molybdenum
Answer:
(b)

(x) Substance which helps to lower the fusion point of the mixture in Hall Heroult Process:
(a) Coke
(b) Concentrated sodium hydroxide
(c) Fluorspar
(d) Concentrated potassium
Answer:
(c) (c) Fluorspar is used in Hall Heroult process to lower the fusion point of the mixture

Section – B
(Attempt any three questions from this Section)

Question 2.
(i) Define: [2]
(a) Isomerism
(b) Ores
Answer:
(a) Isomerism: The process in which the compounds having same molecular formula exist in two or more forms having different structural formula.

(b) Ores: The naturally occurring solid material from which a metal or valuable mineral can be profitably extracted.

(ii) Name the following:
(a) The property by which carbon links with itself to form a long chain.
(b) The saturated hydrocarbons having general formula C_nH_2n-2.
Answer:
(a) Catenation.
(b) This question will have dual answer. Saturated compounds have single bond. Unsaturated compounds have double and triple bond. C_nH_2n-2 → This formula refers to alkynes.

(iii) Draw the structural diagram of: [3]
(a) pentanal
(b) propanol
(c) 2-Butene
Answer:

(iv) Complete and balance the following chemical equations : [3]
(a)

(b) C₂H₆ + O₂ [excess] →
(c) CH₄ + O₂ [excess] →
Answer:
(a)

(b) C₂H₆ + \(\frac{7}{2}\) O₂ → 2CO₂ + 3H₂O
2C₂H₆ + 7O₂ → 4 CO₂ + 6H₂O

(c) CH₄ + 2O₂ → CO₂ + 2H₂O

Question 3.
(i) State the following : [2]
(a) A compound formed when excess ammonia gas reacts with chlorine.
(b) A substance added to water, to manufacture sulphuric acid in Contact process.
Answer:
(a) Ammonium chloride
[8NH₃ + 3Cl₂ → 6NH₄Cl + N₂]

(b) Oleum (H₂S₂O₇)
[H₂S₂O₇ + H₂O → 2H₂SO₄]

(ii) Identify the gas P and Q in the reactions given below : [2]
(а) A compound reacts with an acid to form gas P which has no effect on acidified K₂Cr₂O₇ solution but turns lime water milky.
(b) A metallic nitrate reacts on heating gives oxygen gas along with a coloured gas Q.
Answer:
(a) P is carbon dioxide (CO₂)

(b) Q is Nitrogen dioxide (NO₂)

(iii) State the observation for the following : [3]
(a) Dry ammonia gas reacts with oxygen in the presence of a catalyst.
(b) Excess chlorine gas reacts with ammonia gas.
(c) Carbon reacts with hot concentrated nitric acid.
Answer:
(a) Reddish brown fumes of nitrogen dioxide gas are observed.

(b) Yellow explosive liquid (NCl₃) is formed.
NH₃ + 3Cl₂ → NCl₃ (Yellow explosive liquid) + 3HCl

(c) Reddish brown fumes of nitrogen dioxide gas are observed.
C + 4HNO₃ → CO₂↑ + 2H₂O + 4NO₂↑

(iv) Write balanced equation for the following conservations : [3]
(a) Carbon from cane sugar and concentrated sulphuric acid.
(b) Ferric nitrate from ferric hydroxide and nitric acid.
(c) Ammonium sulphate from ammonium hydroxide and Sulphuric acid.
Answer:

Question 4.
(i) State the relevant reason for the following: [2]
(a) Concentrated alkali is used for the concentration of bauxite ore.
(b) Fused alumina is reduced to aluminium by electrolysis.
Answer:

(a) Concentrated alkali is used for the concentration of bauxite ore because it dissolves aluminium oxide forming soluble sodium aluminate and impurities are left insoluble and can be separated.

(b) Alumina is a very stable compound. Aluminium is more reactive than carbon and it has more affinity for oxygen, therefore, alumina cannot be reduced with carbon but is extracted by electrolytic reduction.

(ii) State one use of the given alloys : [2]
(a) Magnalium
(b) Duralumin
Answer:
(a) Magnalium: It is used for making scientific instruments.
(b) Duralumin: It is used for making aircraft structures.

(iii) Complete the table given below which refers to the Laboratory preparation of Ammonia gas: [3]

Answer:
(a) Sal ammoniac and slaked lime
(NH₄Cl and Ca(OH)₂)
(b) Calcium oxide
(c) Downward displacement of air

(iv) Identify the terms for the following : [3]
(a) The process used to purify Alumina by electrolytic reduction.
(b) The experiment used to demonstrate the high solubility of HC1 gas.
(c) The chemical property of sulphuric acid to form two types of salts with an alkali.
Answer:
(a) Baeyer’s process (Purification of Alumina) Halls and Herault process
(b) Fountain experiment
(c) Dibasic acid

Question 5.
(i) Write the balanced chemical equation for the following : [2]
(a) Action of heat on manganese dioxide and concentrated hydrochloric acid.
(b) Zinc reacts with dilute hydrochloric acid to form zinc chloride.
Answer:
(a)

(b) Zn + 2HCl → ZnCl₂ + H₂ ↑

(ii) Select the right answer from the brackets and complete the statements: [2]
In electrolysis of fused Alumina, the anode is made of (a) ……….. [gas carbon/graphite] and the product formed at cathode is (b) ………….. [oxygen/aluminium].
Answer:
(a) graphite
(b) aluminium

(iii) Give the IUPAC name for the following: [3]

Answer:
(a) Ethene.
(b) Propanal.
(c) 3 methyl pentane.

(iv) Study the diagram, which shows the Brown Ring Test and answer the question given below : [3]

(a) Which ion is determined by Brown Ring Test ?
(b) Why is freshly prepared iron [II] sulphate used in the test ?
(c) Name the substance Z.
Answer:
(a) Nitrate.
(b) Because on exposure to atmosphere it is oxidised to ferric sulphate which does not give brown ring test.
(c) Z is concentrated sulphuric acid.

Question 6.
(i) Distinguish between the following as directed:
(a) Sodium sulphite solution and sodium sulphate solution. [using dilute H₂SO₄]
(b) Lead salt solution and zinc salt solution
[using NH₄OH solution in excess]
Answer:
(a) Na₂SO₃ + H₂SO₄ → Na₂SO₄ + H₂O + SO₂↑
Na₂SO₄ + H₂SO₄ No reaction
Sodium sulphite on reaction with sulphuric acid liberates a pungent-smelling gas sulphur dioxide whereas sodium sulphate does not show any reaction.

(b) PbCl₂ + 2NH₄OH → Pb(OH)₂↓(Chalky white precipitates) + 2NH₄Cl
ZnCl₂ + 2NH₄OH → Zn(OH)₂ + 2NH₄Cl
Zn(OH)₂ + 2NH₄Cl + 2NH₄OH →
[Zn(NH₃)₄ (Soluble complex)] Cl₂ + 4H₂O
Lead salt solution forms white precipitates with excess of ammonium hydroxide whereas zinc salts forms soluble complex.

(ii) Give one word for the following statements:
(a) The compounds of various metals found in nature with ear impurities.
(b) A homogeneous mixture of two or more metals or a metal and a non-metal in specific ratios.
Answer:
(a) Minerals
(b) Alloys

(iii) Identify the acid in each case : [3]
(а) The acid formed when Sulphur reacts with concentrated nitric acid.
(b) An acid, which on adding to lead nitrate solution produces a white precipitate which is soluble on heating.
(c) The acid formed when potassium nitrate reacts with a least volatile acid.
Answer:
(a) Sulphuric acid
[S + 6HNO₃ → H₂SO₄ + 2H₂O + 6NO₂]

(b) Hydrochloric acid
[Pb (NO₃)₂ + 2HCl → PbCl₂ + 2HNO₃]

(c) Nitric acid
[2KNO₃ + H₂SO₄ → K₂SO₄ + 2HNO₃]

(iv) Match column A with column B: [3]

Name (A)	Functional group (B)
1. Aldehyde	(a) -OH
2. Carboxylic acids	(b) -CHO
3. Alcohol	(c) -COOH

Answer:
1. Aldehyde – CHO
2. Carboxylic acids – COOH
3. Alcohol – OH

Solving ICSE Class 10 Chemistry Previous Year Question Papers ICSE Class 10 Chemistry Question Paper 2021 Semester 1 is the best way to boost your preparation for the board exams.

ICSE Class 10 Chemistry Question Paper 2021 Solved Semester 1

Time : 1½ hour
Maximum Marks : 40

General Instructions:

• Answers to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 10 minutes.
• This time is to be spent in reading the question paper.
• The time given at the head of this Paper is the time allowed for writing the answers.
• Attempt all questions from Section A and any three questions from Section B.
• The marks intended for questions are given in brackets [].

SECTION – A
(Attempt all questions)

Question 1.
In the periodic Table, elements of period 3 are arranged in the increasing order of ionization potential as: [1]
(a) B, N, Cl, Ar
(b) Mg, Si, S, Ar
(c) Ar, Si, S, Mg
(d) Si, Ar, Cl, Mg
Answer:
(b) Mg, Si, S, Ar

Size of atoms decrease
Tendency to lose electrons decrease
Hence, ionization potential increase.

Question 2.
If Relative Molecular Mass of Butane (C₄H₁₀) is 58 then its vapour density will be: [1]
(a) 58
(b) 29
(c) 32
(d) 16
Answer:
(b) Molecular mass = Vapour density × 2
Vapour density = \(\frac{\text { M.M. }}{2}=\frac{58}{2}\) = 29

Question 3.
Identify one statement that holds true for electrolysis of molten lead bromide: [1]
(a) Silver grey metal deposits at the anode
(b) Temperature is not maintained during the electrolysis
(c) Brown vapours of bromine are obtained at the anode.
(d) Electrolyte contains H+ ions along with Pb2+ ions
Answer:
(c) PbBr₂(M) ⇌ Pb²⁺(Cathode) + 2Br^-1(Anode)

At anode:
Br^-1 – le^– → Br
Br + Br → Br₂↑
[Reddish brown vapours of bromine are obtained]

Question 4.
The tendency of an atom to attract shared pair of electrons to itself when forming a chemical bond is known as: [1]
(a) Electron affinity
(b) Electronegativity
(c) Ionization potential
(d) Nuclear charge
Answer:
(b) Electronegativity: The tendency to attract shared pair of electrons towards itself.
Example:

Chlorine acquires partial negative charge due to high electronegativity.

Question 5.
Solid sodium chloride does not conduct electricity as: [1]
(a) The strength of the bond is weak
(b) It contains free ions
(c) It does not contain any free ions
(d) It contains free ions as well as molecules
Answer:
(c) (Na⁺)(Cl^–) Solid sodium chloride does not conduct electricity as the ions are held strongly by strong electrostatic forces of attraction. It does not contain any free ions for conduction of electricity.

Question 6.
Elements A and B have electronic configurations 8 and 13 respectively. The chemical formula formed between A and B will be: [1]
(a) AB
(b) B₃A₃
(c) A₂B₃
(d) B₂A₃
Answer:
(d) B₂A₃

Question 7.
The percentage of hydrogen present in NaOH is: (Relative Molecular Mass of NaOH = 40) (At. Wt. of H = 1) [1]
(a) 2.5
(b) 25
(c) 0.25
(d) 0.025
Answer:
(a) NaOH = 23 + 16+ 1 = 40
% of hydrogen = \(\frac{\text { Mass of hydrogen }}{\text { Total weight }}\) × 100
= \(\frac{1}{40}\) × 100 = 2.5

Question 8.
A salt formed by incomplete neutralization of an acid by a base :
(a) Basic salt
(b) Acid salt
(c) Normal salt
(d) Complex salt
Answer:
(b)

Incomplete neutralization results in acid salt and complete neutralization results in normal salt.

Question 9.
The colour of the precipitate formed after the addition of a small amount of sodium hydroxide solution to an aqueous solution of ferric chloride is: [1]
(a) gelatinous white
(b) pale blue
(c) reddish brown
(d) dirty green
Answer:
(c) FeCl₃ + 3NaOH → Fe(OH)₃ ↓ + 3NaCl (Reddish brown precipitates)

Question 10.
Alkaline earth metals have the same:
(a) number of valence electrons
(b) number of shells
(c) metallic property
(d) ionization potential
Answer:
(a)

Question 11.
Which of the following compounds neither dissociate nor ionise in water? [1]
(a) Hydrochloric acid
(b) Sodium hydroxide
(c) Potassium Nitrate
(d) Carbon tetrachloride
Answer:
(d) All ionic compounds dissociate in water. Only covalent compounds do not dissociate as they do not form ions.
HCl ⇌ H⁺ + Cl^–
NaOH ⇌ Na⁺ + OH^–
KNO₃ ⇌ K⁺ + NO^–₃

Question 12.
The table shows the electronic configuration of four elements. [1]

Element	Electronic Configuration
W	2, 6
X	2, 8
Y	2, 8,1
Z	2, 8,7

Which pair of atoms will form a covalent compound?
(a) two atoms of W
(b) two atoms of X
(c) an atom of W and an atom of X
(d) an atom of Y and an atom of Z
Answer:
(a) Two atoms of W

Question 13.
Element with an atomic number 19 will: [1]
(a) accept an electron and get oxidized
(b) accept an electron and get reduced
(c) lose an electron and get oxidized
(d) lose an electron and get reduced
Answer:
(c)

It will lose one electron and hence gets oxidized.

Question 14.
Which of the following has two sets of lone pair of electrons in them? [1]
(a) Ammonia
(b) Methane
(c) Water
(d) Ammonium ion
Answer:
(c)

Question 15.
If the empirical mass of the formula PQ₂ is 10 and the Relative Molecular Mass is 30, then the molecular formula will be: [1]
(a) PQ₂
(b) P₃Q₂
(c) P₆Q₂
(d) P₃Q₆
Answer:
(d) Empirical mass = 10
Relative molecular mass = 30
n = \(\frac{\text { R.M.M. }}{\text { E.M. }}=\frac{30}{10}\) = 3
M.F. = (E.F.)_n
= (PQ₂)₃
= P₃Q₆

Question 16.
Which of the following is a tribasic acid? [1]
(a) H₂SO4
(b) Al(OH)₃
(c) H₃PO₄
(d) Ca(OH)₂
Answer:
(c) H₃PO₄ ⇌ 3H⁺ + PO₄^3-
The acid which gives three hydrogen ions to be neutralized by hydroxyl ions of base is known as tribasic acid.

Question 17.
If a solution of an electrolyte mixture has calcium ions, cupric ions, zinc ions and magnesium ions, which of these ions would you see preferentially discharged at the cathode? [1]
(a) Calcium ions
(b) Zinc ions
(c) Cupric ions
(d) Magnesium ions
Answer:
(c) The ions which are present at the bottom of reactivity series are preferentially discharged.

Question 18.
Which of the following ions will readily discharge at the anode during the electrolysis of acidulated water? [1]
(a) OH
(b) SO₄^2-
(c) Cl^–
(d) H⁺
Answer:
(a) OH^– ions are readily discharged during electrolysis of acidulated water.
H₂SO₄ ⇌ 2H⁺ + SO₄^2-

At anode: Both SO₄^2- and OH^– migrate, but OH^– ions are discharged.
4OH^– ⇌ 2H₂O + O₂↑

Question 19.
If the imperial formula of a compound is CH and its vapour density is 13, then its molecular formula will be: [ 1 ]
(At. Wt. C=12, H=l)
(a) CH
(b) C₂H₂
(c) C₄H₄
(d) C₃H₃
Answer:
(b) Empirical formula CH
Vapour density = 13
Empirical formula mass = 12 + 1 = 13
Molecular mass = 2 × VD
= 2 × 13 = 26
n = \(\frac{\text { Molecular mass }}{\text { Empirical mass }}\)
= \(\frac{26}{13}\) = 2
Molecular formula = (Empirical formula)_n
= (CH)₂
= C₂H₂

Question 20.
Aqueous solution of Cupric chloride forms a deep blue solution on addition of: [1]
(a) dropwise sodium hydroxide
(b) excess sodium hydroxide
(c) dropwise ammonium hydroxide
(d) excess ammonium hydroxide
Answer:
(d) CuCl₂ + 2NH₄OH → CU(OH)₂↓ + 2NH₄Cl
CU(OH)₂ + 2NH₄Cl + 2NH₄OH → 4H₂O + [CU(NH₃)₄] Cl₂ (Deep blue solution) (Tetraamine copper chloride)

Question 21.
Which statement about conduction of electricity is correct? [1]
(a) Electricity is conducted in aqueous solution by electrons
(b) Electricity is conducted in a metal wire by ions
(c) Electricity is conducted in a molten electrolyte by electrons
(d) Electricity is conducted in an acid solution by ions
Answer:
(d) Acid splits to form ions and these ions are responsible for conduction of electricity.

Question 22.
If an element has low ionization potential, then it is likely to be a: [1]
(a) metal
(b) metalloid
(c) non metal
(d) inert gas
Answer:
(a) The bigger the size, easier it is to lose electrons and hence lower is the ionization potential. Since, alkali metal has big size; it has low ionization potential.

Question 23.
Which electron arrangement for the outer shell electrons in a covalent compound is correct? [1]

Answer:
(c)

Question 24.
The products formed when an acid reacts with a base is:
(a) salt and hydrogen
(b) salt and oxygen
(c) salt and water
(d) salt and carbon dioxide
Answer:
(c) Acid + Base → Salt + Water
HCl + NaOH → NaCl (Salt) + H₂O (Water)
This reaction is known as neutralization reaction.

Question 25.
In the circuit below, the lamp lights up. What could X be?

(a) a solution of alcohol in water
(b) a solution of sodium chloride in water
(c) sugar solution
(d) solid potassium chloride
Answer:
(b) Only sodium chloride can form ions in water. Hence, it is the only solution that can conduct electricity.

Question 26.
Which one of the following is a non-metallic cation? [1]
(a) K⁺
(b) NH₄⁺
(c) Cu²⁺
(d) Na⁺
Answer:
(b) K⁺, Cu²⁺, Na⁺ are all metallic ions. Only ammonium ion (NH₄⁺) is a non metallic cation.

Question 27.
Type of bonding present in hydrogen chloride: [1]
(a) metallic
(b) ionic
(c) covalent
(d) coordinate
Answer:
(c)

Question 28.
The non-metallic properties of elements from left to right in a Periodic Table: [1]
(a) increases
(b) decreases
(c) remains same
(d) first increases and then decreases
Answer:
(a) As we move along the period, the number of valence electrons increase, the hold of nucleus increase, tendency to lose electron decrease and metallic character increase.

Question 29.
The aqueous solution that contains both ions and molecules: [1]
(a) sulphuric acid
(b) nitric acid
(c) acetic acid
(d) hydrochloric acid
Answer:
(c)

Acetic acid is a weak acid. It does not dissociate completely. Hence, it contains both ions as well as molecules.

Question 30.
The basic oxide which is an alkali: [1]
(a) Copper oxide
(b) Sodium oxide
(c) Ferric oxide
(d) Zinc oxide
Answer:
(b) The main three alkalis are sodium hydroxide, potassium hydroxide and ammonium hydroxide.
Hence, sodium oxide is the basic oxide which is an alkali.
Na₂O + H₂O → 2NaOH

Question 31.
If the pH of a solution is ‘2’ then solution is a: [1]
(a) strong acid
(b) strong alkali
(c) weak acid
(d) weak alkali
Answer:
(a) Lower the value of pH, more is the acidic character. Hence, a solution with pH 2 is more acidic.

Question 32.
The acidity of aluminium hydroxide is: [1]
(a) 3
(b) 1
(c) 4
(d) 2
Answer:
(a) Al(OH)₃ ⇌ Al³⁺ + 3OH^-1
Acidity is the number of hydroxyl ions furnished to be neutralised with H⁺ ions of an acid.

Question 33.
Hydracids are those acids which contain: [1]
(a) Hydrogen with any metal
(b) Hydrogen, a non-metal and oxygen
(c) Hydrogen and a non-metal other than oxygen
(d) Hydrogen and oxygen only
Answer:
(c) Hydracids are compounds of hydrogen and non-metals like HCl, HBr, HF, HI.

Question 34.
The oxidation reaction among the following is : [1]
(a) Fe³⁺ + 3e^– → Fe
(b) Fe²⁺ – 1e^– → Fe³⁺
(c) Cl₂ + 2e^– → 2Cl^1-
(d) Cu²⁺ + 2e^– → Cu
Answer:
(b)

Question 35.
A student added excess of sodium hydroxide solution to each of the salt solution. An insoluble precipitate formed was observed in: [1]
(a) Calcium nitrate
(b) Zinc nitrate
(c) Lead nitrate
(d) Sodium nitrate
Answer:
(a) Excess of sodium hydroxide leads to formation of insoluble precipitates. Only in case of calcium nitrate zinc nitrate and lead nitrate form soluble complex sodium zincate and sodium plumbate respectively. Sodium nitrate is soluble completely and excess of sodium hydroxide has no effect.

Question 36.
Which apparatus could be used to electroplate an iron nail with copper? [1]

Answer:
(a) The article to be electroplated is always made cathode. The electrolyte must contain the same ions with which it has to be electroplated.

Question 37.
The table below shows the electronic arrangements of six atoms, A to F.

With respect to the table select the following:
(i) Two atoms from the same group of the periodic table: [1]
(a) D and E
(b) C and D
(c) E and F
(d) C and E
Answer:
(b) Two atoms from the same group of the periodic table must contain same valence electrons. Hence, C and D both having 6 electrons belong to the same group.

(ii) Two noble gases: [1]
(a) A and B
(b) E and F
(c) B and E
(d) D and E
Answer:
(c) B has configuration 2 that means it is helium and E has configuration 2, 8, 8 which refers to Argon. Helium shows fully filled duplet and argon shows fully filled octet. Thus, both B and E are noble gases.

(iii) The atom which is the most electronegative: [1]
(a) A
(b) B
(c) C
(d) F
Answer:
(c) A, C and D are electronegative. As all the three have tendency to gain electron. But C has the maximum tendency out of the three because of its smallest size.

(iv) The atom which has the highest ionization potential: [1]
(a) A
(b) B
(c) E
(d) F
Answer:
(b) The highest ionization potential is of B (Helium). As it is the most stable, having smallest size, therefore, the energy required to remove electron from its outermost shell is maximum.

Solving ICSE Class 10 Physics Previous Year Question Papers ICSE Class 10 Physics Question Paper 2020 is the best way to boost your preparation for the board exams.

ICSE Class 10 Physics Question Paper 2020 Solved

Time : 2 hours
Maximum Marks: 80

General Instructions:

• Answers to this Paper must be written on the paper provided separately.
• You will not be allowed to write during the first 15 minutes.
• This time is to be spent in reading the Question paper.
• The time given at the head of this Paper is the time allowed for writing the answers.
• Section I is compulsory. Attempt any four questions from Section II.
• The intended marks for questions or parts of questions are given in brackets [].

SECTION – I (40 marks)
Attempt all questions from this Section.

Question 1.
(a) (i) Define moment of force. (2)
(ii) Write the relationship between the SI and CGS unit of moment of force.
Answer:
(i) It is defined as the product of force and the arm of the couple.
(ii) 1 n m = 10⁷ dyn cm

(b) Define a kilowatt hour. How is it related to joule ? (2)
Answer:
It is the defined as the energy consumed when an agent of 1 kilowatt is used for 1 hour.
1 kWh = 3.6 × 10⁶J

(c) A satellite revolves around a planet in a circular orbit. What is the work done by the satellite at any instant? Give a reason. (2)
Answer:
Zero. As the centripetal force acts on the satellite perpendicular to its motion.

(d) (i) Identify the class of the lever shown in the diagram below : (2)

(ii) How is it possible to increase the M.A. of the above lever without increasing its length ?
Answer:
(i) Third class.
(ii) By increasing its effort arm i.e., increasing FE

(e) Give one example of each when : (2)
(i) Chemical energy changes into electrical energy.
(ii) Electrical energy changes into sound energy.
Answer:
(i) Electrochemical cell
(ii) Loud speaker.

Question 2.
(a) A crane ‘A’ lifts a heavy load in 5 seconds, whereas another crane ‘B’ does the same work in 2 seconds. Compare the power of crane ‘A’ to that of crane ‘B’ (2)
Answer:
Power is inversely proportional to timc, thus from the expression P = \(\frac{\mathrm{W}}{t}\) we have
\(\frac{P_A}{P_B}\) = \(\frac{t_{\mathrm{B}}}{t_{\mathrm{A}}}\) = \(\frac{2}{5}\) = 0.4

(b) A ray of light falls normally on a rectangular glass slab. (2)
Draw a ray diagram showing the path of the ray till it emerges out of the slab.
Answer:
The ray diagram is as shown.

(c) Complete the path of the mono-chromatic light ray AB incident on the surface PQ of the equilateral glass prism PQR till it emerges out of the prism due to refraction. (2)

Answer:
The path of the rays is as shown.

(d) Where should an object be placed in front of a convex lens in order to get: (2)
(i) an enlarged real image
(ii) enlarged virtual image ?
Answer:
(i) Beyond 2F (i) Between optical centre and the focus.

(e) A pond appears to be 2.7 in deep. If the refractive index of water is \(\frac{4}{3}\), find the actual depth of the pond. (2)
Answer:
AD = 2.7, µ = 4/3, RD
We know that RD = µ × AD = 4/3 × 2.7
= 3.6m

Question 3.
(a) The wave lengths for the light of red and blue colours are nearly 7.8 × 10^-7 m and 4.8 × 10^-7 m respectively.
(i) Which colour has the greater speed in a vacuum ?
(ii) Which colour has a greater speed in glass ? (2)
Answer:
(i) Both have the same speed in vacuum.
(ii) Red tight has more speed in glass.

(b) Draw a graph between displacement from mean position and time for a body executing free vibration in a vacuum. (2)
Answer:
The graph is as shown

(c) A sound wave travelling in water has wavelength 0.4 m. (2)
Is this wave audible in air ? (The speed of sound in water = 1400 ms^-1)
Answer:
Given λ = 0.4 m,
Using the relation V = vλ
We have v = V/λ = 1400/0.4 = 3500 Hz
Since this lies in the audible range (20 to 20000 Hz) it will be audible.

(d) Why does stone lying in the sun get heated up much more than water lying for the same duration of time? (2)
Answer:
Because water has a large specific heat while stone has a small specific heat.

(e) Why is it not advisable to use a piece of copper wire as fuse wire in an electric circuit? (2)
Answer:
Because copper has a high melting point. It will not melt easily when a high electric current passes through it and may damage the electrical appliances.

Question 4.
(a) Calculate the total resistance across AB: (2)

Answer:
Resistors of resistance 6Ω and 3Ω are in parallel therefore, we have R_p = \(\frac{6 \times 3}{6+3}\) = 2Ω. This is in series with the 5Ω resistors, hence total resistance is 2 + 5 = 7Ω

(b) Two metallic blocks P and Q having masses in ratio 2:1 are supplied with the same amount of heat. If their temperatures rise by same degree, compare their specific heat capacities. (2)
Answer:
Given \(\frac{m_{\mathrm{P}}}{m_{\mathrm{Q}}}\) = \(\frac{2}{1}\), We know that Q = m c θ, since Q and q are same therefore, we have \(\frac{c_{\mathrm{P}}}{c_{\mathrm{Q}}}\) = \(\frac{m_{\mathrm{Q}}}{m_{\mathrm{P}}}\) = \(\frac{1}{2}\)

(c) When a current carrying conductor is placed in a magnetic field, it experiences a mechanical force. What should be the angle between the magnetic field and the length of the conductor so that the force experienced is : (2)
(i) Zero
(ii) Maximum ?
Answer:
The expression for force is F = B I L sin θ
(i) Zero force will be for θ = 0°
(ii) Maximum force will be for θ = 90°

(d) A nucleus ₈₄X²⁰² of an element emits an alpha particle followed by a beta particle. The final nucleus is _aY^b. Find a and b. (2)
Answer:
The scheme of decay is
,
therefore a = 83, b = 198

(e) The diagram below shows a loop of wire carrying current I: (2)

(i) What is the magnetic polarity of the loop that faces us?
(ii) With respect to the diagram how can we increase the strength of the magnetic field produced by this loop?
Answer:
(i) South Pole.
(ii) By decreasing the resistance of the circuit. This will increase the current and hence the magnetic field of the loop.

SECTION – II (40 marks)
Attempt any four questions from this Section.

Question 5.
(a) The figure below shows a simple pendulum of mass 200 g. It is displaced from the mean position A to the extreme position B. The potential energy at the position A is zero. At the position B the pendulum bob is raised by 5 m. (3)

(i) What is the potential energy of the pendulum at the position B ?
(ii) What is the total mechanical energy at point C ?
(iii) What is the speed of the bob at the position A when released from B ?
(Take g= 10 ms^-2 and there is no loss of energy.)
Answer:
(i) Potential energy at position B is = mgh = 0.2 × 10 × 5 = 10 J
(ii) Total mechanical energy = potential energy at point B = 10 J
(iii) For position A: 1/2 mv² = mgh, v = \(\sqrt{2 g h}\) = \(\sqrt{2 \times 10 \times 5}\)
= 10 ms^-1

(b) (i) With reference to the direction of action, how does a centripetal force differ from a centrifugal force during uniform circular motion ? (3)
(ii) Is centrifugal force the force of reaction of centripetal force ?
(iii) Compare the magnitudes of centripetal and centrifugal force. (3)
Answer:
(i) Centripetal force is directed inwards towards the centre of the circular path while centriftigal force is directed outwards/ away from the centre of the circular path.
(ii) No
(iii) They are equal in magnitude.

(c) A block and tackle system of pulleys has velocity ratio 4. (4)
(i) Draw a neat labelled diagram of the system indicating clearly the points of application and direction of load and effort.
(ii) What will be its V.R. if the weight of the movable block is doubled ?
Answer:
(i) The labelled diagram is as shown.

(ii) There is no change in the velocity ratio i.e., it will remain 4

Question 6.
(a) A diver in water looks obliquely at an object AB in air. [3]

(i) Does the object appear taller, shorter or of the same size to the diver ?
(ii) Show the path of two rays AC and AD starting from the tip of the object as it travels towards the diver in water and hence obtain the image of the object.
Answer:
(i) Taller
(ii) The diagram is as shown.

(b) Complete the path of the ray AB through the glass prism in PQR till it emerges out of the prism. Given the critical angle of the glass as 42°. [3]

Answer:
The path of the ray is as shown.

(c) A lens of focal length 20 cm forms an inverted image at a distance 60 cm from the lens. [4]
(i) Identify the lens.
(ii) How far is the lens present in front of the object’ ?
(iii) Calculate the magnification of the image.
Answer:
Given f = 20 cm, y = 60 cm
(i) Convex lens
(ii) Using the expression \(\frac{1}{f}\) = \(\frac{1}{v}\) = \(\frac{1}{u}\) we have
\(\frac{1}{u}\) = \(\frac{1}{v}\) – \(\frac{1}{f}\) = \(\frac{1}{60}\) – \(\frac{1}{20}\)
= \(\frac{1-3}{60}\) = –\(\frac{2}{60}\) = –\(\frac{1}{30}\)
or u = -30 cm
(iii) Magnification is given by
m = \(\frac{v}{u}\) = \(\frac{60}{-30}\) = -2

Question 7.
(i) Give reasons for the following : [3]
During the day :
(i) Clouds appear white.
(ii) Sky appears blue,
Answer:
(i) Clouds are at much lower height. They are seen due to scattering of light due to lower parts of earth’s atmosphere, which contains large dust particles, water droplets, ice particles etc. As the size of scatterer (these molecules) is much greater than the wavelength of light, Rayleigh scattering is not valid. Rather, all wavelengths are scattered nearly equally. Therefore all equally scattered colours merge to give us the sensation of white. Hence, clouds generally appear white.

(ii) The molecules of air and other fine particles in the atmosphere have size comparable to the wavelength of visible light. These are therefore, more effective in scattering light of shorter wavelengths at the blue end than light of longer wavelengths at the red end. Thus, when sunlight passes through the atmosphere, the fine particles in air scatter the blue colour (shorter wavelengths) more strongly than red. The scattered blue light enters our eyes and makes the sky appear blue.

(b) (i) Name the system which enables us to locate underwater objects by transmitting ultrasonic waves and detecting the reflecting impulse. [3 ]
(ii) What are acoustically measurable quantities related to pitch and loudness ?
Answer:
(i) SONAR
(ii) Frequency and Intensity of sound.

(c) (i) When a tuning fork [vibrating] is held close to ear, one hears a faint hum. The same [vibrating tuning fork] is held such that its stem is in contact with the table surface, then one hears a loud sound. Explain. [4]
(ii) A man standing in front of a vertical cliff fires a gun. He hears the echo after 3.5 seconds. On moving closer to the cliff by 84 m, he hears the echo after 3 seconds. Calculate the distance of the cliff from the initial position of the man.
Answer:
(i) This is due to the phenomenon of resonance, the table also begins to vibrate with the same frequency as that of the tuning fork and produces large sound.
(ii) In the first case, we have
V = \(\frac{2 d}{t}\) = \(\frac{2 d}{3.5}\) … (i)
In the second case, we have
V = \(\frac{2 d}{t}\) = \(\frac{2(d-84)}{3}\) … (ii)
From (i) and (ii) we have
\(\frac{2 d}{3.5}\) = \(\frac{2(d-84)}{3}\)
Or 6d = 7d – 588 or d = 588 m

Question 8.
(a) The diagram below shows the core of a transformer and its input and output connections. [3]

(i) State the material used for the core.
(ii) Copy and complete the diagram of the transformer by drawing input and output coils.
Answer:
(i) Soft iron
(i) The diagram is as shown.

(b) (i) What are superconductors ? [3]
(ii) Calculate the current drawn by an appliance rated 110 W, 220 V when connected across 220 V supply.
(iii) Name a substance whose resis-tance decreases with the increase in temperature.
Answer:
(i) These are the substances which have zero resistance at low temperatures.
(ii) I = P/V= 110/ 220 = 0.5 A
(iii) Mercury

(iii)We know that semiconductor’s resistance decreases with the increase in temperature.
For examples : Silicon, Graphite, etc.

(c)

The diagram above shows three resistors connected across a cell of e.m.f. 1.8 V and internal resistance r. Calculate :
(i) Current through 3 Ω resistor.
(ii) The internal resistance r.
Answer:
(i) I₃ = \(\frac{\mathrm{R}_{1.5} \mathrm{I}}{\mathrm{R}_{1.5}+\mathrm{R}_3}\) = \(\frac{1.5 \times 0.3}{1.5+3}\) = 0.1A
(ii) Resistors 3Ω and 1.5Ω are connected in parallel.
Therefore their net resistance is
R_P = \(\frac{1.5 \times 3}{1.5+3}\) = \(\frac{4.5}{4.5}\) = 1Ω
This is in series with the 4Ω resistor and internal resistance of the cell r, hence total resistance of the circuit is
R_S = 1 + 4 + r = 5 + r
Now V = IR, therefore we have
1.8 = 0.3(5 + r)
Or r = 1Ω

Question 9.
(a) (i) Define heat capacity of a substance. [3]
(ii) Write the SI unit of heat capacity.
(iii) What is the relationship between heat capacity and specific beat capacity of a substance ?
Answer:
(i) Specific heat (c) of a material is defined as the amount of heat required in raising the temperature of a unit mass of a substance through 1 °C or 1 K.
(ii) In SI unit of heat capacity is J K^-1

(b) The diagram below shows the change’ of phases of a substance on a temperature vs time graph on heating the substance at a constant rate. [3]

(i) Why is the slope of CD less than slope of AB ?
(ii) What is the boiling and melting point of the substance ?
Answer:
(i) From section CD the specific heat is high as compared to section AB
(ii) t₂ and t₁ respectively

(c) A piece of ice of mass 60 g is dropped into 140 g of water at 50°C. Calculate the final temperature of water when all. the ice has melted. [4]
(Assume no heat is Inst to the surrounding)
Specific heat capacity of water = 4.2 Jg^-1 k^-1
Specific latent heat of fusion of ice = 336 Jg^-1
Answer:
Given m_ice = 60 g = 60 × 10^-3 kg, m_w = 140g
= 140 × 10^-3 kg, T₁ = 50°C, Specific heat capacity of water
= 4.2Jg^-1k^-1
Specific latent heat of fusion of ice = 336 J g^-1
Let the final temperature be T.
Now
Heat lost by water = Heat gained by ice
m_wc_w Δt = m_iceL_{i ice} + m_ice c_w Δt
140 × 10^-3 × 4.2 × 10³ × (50 – T)
= 60 × 10^-3 × 336 × 10³ + 60 × 10^-3 × 4.2 × 10³ × (T – 0)
588 × (50 – T) = 20160 + 252T
29400 – 588 T = 20160 + 252 T
840 T = 9240
T = 11°C

Question 10.
(a) (i) Draw a neat labelled diagram of a d.c. motor. (3)
(ii) Write any one use of a d.c. motor.
Answer:
(i) A neat and labelled diagram is as shown.

(ii) It is used in tape recorder CD players.

(b) (i) Differentiate between nuclear fusion and nuclear fission. (3)
(ii) State one safety precaution in the disposal of nuclear waste.
Answer:
(i) In nuclear fission a heavy nucleus splits into two or more smaller nuclei while in nuclear fusion two small nuclei fuse to form a heavy nucleus.
(ii) Nuclear waste should be disposed off in lead containers.

(c) An atomic nucleus A is composed of 84 protons and 128 neutrons. The nucleus A emits an alpha particle and is transformed into a nucleus B. (4)
(i) What is the composition of B ?
(ii)The nucleus B emits a beta particle and is transformed into a nucleus C. What is the composition of C ?
(iii) What is mass number of the nucleus A ?
(iv) Does the composition of C change if it emits gamma radiations ?
Answer:
(i) The reaction is as follows

The composition of B is 82 protons and 126 neutrons
(ii) The reaction is as follows.

The composition of B is 83 protons and 126 neutrons
(iii) Mass number of A = 212
(iv) No