Chemical Reactions and Equation – CBSE Class 10 Science – Extra Questions

According to new CBSE Exam Pattern, MCQ Questions for Class 10 Science pdf Carries 20 Marks. https://meritbatch.com/chemical-reactions-and-equation-cbse-class-10-science-extra-questions/

Topics and Sub Topics Covered in NCERT Solutions for Class 10 Science Chapter 1.

Section Name	Topic Name
1	Chemical Reactions And Equations
1.1	Chemical Equations
1.2	Types Of Chemical Reactions
1.3	Have You Observed The Effects Of Oxidation Reactions In Everyday Life? Y Life?

Class 10 Science Chapter 1 Extra Questions
Question-1
What is the method of balancing chemical equation?
Solution:
Hit and trial method is used for balancing simple chemical equations. In this method, coefficients before the symbols/formulae of the reactants and products are adjusted in such a way that the total number of atoms of each element on both the sides becomes equal.

Extra Questions For Class 10 Science Chapter 1
Question-2
Why is it necessary to balance a chemical equation?
Solution:
We know that, according to the law of conservation of mass, the total mass of all the atoms present in the reactants should be equal to that of all the atoms present in the products. This law will hold good only when the number of atoms of all types of elements on both sides is equal. Thus balancing of chemical equation is necessary so that the law of conservation of mass may be obeyed.

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Chemical Reaction And Equation Class 10 Extra Questions
Question-3
In the equations given below, state giving reasons, whether substances have been oxidised or reduced.
(i) PbO + CO –> Pb + CO₂
(ii) H₂S + Cl₂–>2HCl + S.
Solution:
(i) Carbon monoxide is oxidised as it gains oxygen.
(ii) Chlorine is reduced as it gains hydrogen.

Chemical Reactions And Equations Extra Questions
Question-4
A sample of water weed was placed in water and exposed to sunlight. Bubbles of a gas are seen on the surface of the leaves.
(i) Name the gas evolved.
(ii) Name the process taking place.
(iii) Write a balanced equation of reaction taking place.
Solution:
(i) Oxygen
(ii) Photosynthesis
(iii) 6CO₂ + 6H₂O —> C₆H₁₂O₆ + 6O_2.

Ch 1 Science Class 10 Extra Questions
Question-5
Give balanced equations, wherever possible, or where this is not possible, explain the following by means of examples:
i) A reaction which gives out heat.
ii) A reaction which takes place with the help of sunlight.
iii) A reaction which is brought about by electric current.
iv) A reversible reactions.
(v) A reaction with a solid and gas which produces heat.
Solution:

Class 10 Science Ch 1 Extra Questions
Question-6
Balance the following chemical equations:

Chemical Reactions And Equations Class 10 Extra Questions Pdf
Question-7
Write the uses of decomposition reactions.
Solution:
The decomposition reactions carried out by electricity are used to extract several metals from their naturally occurring compounds like chlorides and oxides.
When passing electricity decomposes the fused metal chloride or metal oxide, then metal is produced at the cathode.

Class 10 Chemistry Chapter 1 Extra Questions
Question-8
What are the characteristics of chemical reactions?
Solution:
1. Evolution of a gas
2. Formation of a precipitate
3. Change in colour
4. Change in temperature
5. Change in state.

Class 10 Science Chapter 1 Extra Questions With Solutions
Question-9
Can rancidity retarded by storing foods away from light?
Solution:
In the absence of light, the oxidation of fats and oils present in food is slowed down and hence the development of rancidity is retarded.

Extra Questions Of Chemical Reactions And Equations
Question-10
What are the different ways can make more informative about the chemical equation?
Solution:
1. By indicating the “physical states” of the reactants and products.
2. By indicating the “heat changes” taking place in the reaction.
3. By indicating the “conditions” under which the reaction takes place.