Worksheet (Ch 1: Chemical Reactions and Equations)

This worksheet contains practice questions for Class 10 Science, Chapter 1: Chemical Reactions and Equations. These questions are based on CBSE board curriculum as per NCERT textbook.

By practicing these questions, you will be able to get an idea of what type of questions may appear in the examination.

Question 1:
Write a balanced chemical equation with state symbols for the following reactions.
(i) Solutions of barium chloride and sodium sulfate in water react to give insoluble barium sulfate and the solution of sodium chloride.
(ii) Sodium hydroxide solution (in water) reacts with hydrochloric acid solution (in water) to produce sodium chloride solution and water.

Question 2:
What happens when dilute hydrochloric acid is added to iron fillings?
(a) Hydrogen gas and iron chloride are produced.
(b) Chlorine gas and iron hydroxide are produced.
(c) No reaction takes place.
(d) Iron salt and water are produced.

Question 3:
Which of the statements about the reaction below are incorrect?
2PbO(s) + C(s) → 2Pb(s) + CO2(g)
(a) Lead is getting reduced.
(b) Carbon dioxide is getting oxidized.
(c) Carbon is getting oxidized.
(d) Lead oxide is getting reduced.
(i) (a) and (b)
(ii) (a) and (c)
(iii) (a), (b) and (c)
(iv) all

Question 4:
Balance the following chemical equations.
HNO3 + Ca(OH)2 → Ca(NO3)2 + H2O
NaOH + H2SO4 → Na2SO4 + H2O
BaCl2 + H2SO4 → BaSO4 + HCl

Question 5:
Fe2O3 + 2Al → Al2O3 + 2Fe
The above reaction is an example of a
(a) combination reaction.
(b) double displacement reaction.
(c) decomposition reaction.
(d) displacement reaction.

Question 6:
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Question 7:
What is the difference between displacement and double displacement reactions? Write equations for these reactions.

Question 8:
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

Question 9:
Oil and fat containing food items are flushed with nitrogen. Why?

Question 10:
Identify the substances that are oxidized and the substances that are reduced in the following reactions.
(i) 4Na(s) + O2(g) → 2Na2O(s)
(ii) CuO(s) + H2(g) → Cu(s) + H2O(l)

Question 11:
A solution of a substance ‘X’ is used for whitewashing.
(i) Name the substance ‘X’ and write its formula.
(ii) Write the reaction of the substance ‘X’ named in (i) above with water.

Question 12:
Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.

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