Chemical Reactions and Equations

 

Class 10 Science – Practice Question Paper

Chapter: Chemical Reactions and Equations
Maximum Marks: 20
Time: 45 Minutes

Section A (1 mark each)

1. Define a chemical reaction.

2. Write the balanced chemical equation for the reaction between hydrogen gas and oxygen gas to form water.

3. What is meant by a balanced chemical equation? Why should chemical equations be balanced?

4. Name the type of reaction:

   • (i) Burning of magnesium ribbon in air

   • (ii) Rusting of iron

5. What is a precipitation reaction? Give an example with a balanced equation.

Section B (2 marks each)

6. What is the difference between a combination reaction and a decomposition reaction? Give one example for each.

7. Write the balanced chemical equation for the following and identify the type of reaction:

   • (a) Zinc reacts with hydrochloric acid

   • (b) Copper sulfate reacts with iron

8. A solution of lead nitrate is mixed with a solution of potassium iodide. Write the balanced chemical equation for the reaction and state the type of reaction.

Section C (3 marks each)

9. Explain redox reactions with the help of an example.

10. What is corrosion? How does it affect metals? Mention two ways to prevent corrosion.

11. (a) What happens when baking soda (NaHCO₃) is heated? Write the chemical equation.
    (b) What is observed when quicklime is added to water? Write the equation.

Section D (4 marks each)

12. Balance the following chemical equations and mention the type of reaction:

• (a) Na + H₂O → NaOH + H₂

• (b) BaCl₂ + Al₂(SO₄)₃ → BaSO₄ + AlCl₃

• (c) CaCO₃ → CaO + CO₂

• (d) Fe + CuSO₄ → FeSO₄ + Cu

13. Consider the reaction:
    $2KClO₃ → 2KCl + 3O₂$

    • (a) Name the type of reaction.

    • (b) What is the role of heat in this