Worksheet: 1 2026

 Here are 20 multiple-choice questions (MCQs) based on the Chapter: Chemical Reactions and Equations for Class 10, as per the CBSE syllabus:

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1. Which of the following is 

a chemical change?

a) Melting of ice

b) Boiling of water

c) Rusting of iron

d) Breaking of glass

2. The chemical formula

 of quicklime is:

a) CaCO₃

b) Ca(OH)₂

c) CaO

d) CaCl₂

3. Which of the following

 is a decomposition reaction?

a) 2H₂ + O₂ → 2H₂O

b) Zn + H₂SO₄ → ZnSO₄ + H₂

c) 2KClO₃ → 2KCl + 3O₂

d) AgNO₃ + NaCl → AgCl + NaNO₃

4. Which gas is evolved when 

zinc reacts with dilute hydrochloric acid?

a) Oxygen

b) Carbon dioxide

c) Hydrogen

d) Nitrogen

5. Which of the following is

 an example of a combination reaction?

a) CaO + H₂O → Ca(OH)₂

b) 2KClO₃ → 2KCl + 3O₂

c) CuSO₄ + Zn → ZnSO₄ + Cu

d) BaCl₂ + Na₂SO₄ → BaSO₄ + NaCl

6. A chemical equation is said

 to be balanced when:

a) The number of atoms of each 

element is the same on both sides

b) The physical states are mentioned

c) The number of molecules is equal

d) The total mass is doubled

7. What type of reaction is

 respiration in human beings?

a) Combination

b) Displacement

c) Decomposition

d) Oxidation

8. In a redox reaction:

a) Only oxidation occurs

b) Only reduction occurs

c) Both oxidation and reduction occur

d) Neither oxidation nor reduction occurs

9. The brown coating on iron

 after rusting is:

a) Fe

b) Fe₂O₃·xH₂O

c) Fe₃O₄

d) FeO

10. Which of the following 

is not a physical change?

a) Freezing of water

b) Burning of paper

c) Dissolving sugar in water

d) Boiling of alcohol

11. Which of the following reactions is an example of a displacement reaction?

a) NaOH + HCl → NaCl + H₂O

b) Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂

c) C + O₂ → CO₂

d) CaCO₃ → CaO + CO₂

12. When lead nitrate is heated, it gives:

a) Lead oxide, nitrogen dioxide, and oxygen

b) Lead nitrate and oxygen

c) Lead sulfate and carbon dioxide

d) Lead and nitrogen gas

13. A reaction in which energy is

 absorbed is called:

a) Exothermic reaction

b) Endothermic reaction

c) Redox reaction

d) Combination reaction

14. Which of the following

 represents a neutralization reaction?

a) Zn + HCl → ZnCl₂ + H₂

b) HCl + NaOH → NaCl + H₂O

c) CaCO₃ → CaO + CO₂

d) AgNO₃ + NaCl → AgCl + NaNO₃

15. Which of the following will not

 show displacement reaction?

a) Fe + CuSO₄

b) Zn + FeSO₄

c) Ag + CuSO₄

d) Cu + AgNO₃

16. A white precipitate is formed

 when barium chloride reacts with:

a) HCl

b) Na₂SO₄

c) KNO₃

d) NH₄OH

17. What change is observed

 when copper is heated in air?

a) Becomes black

b) Becomes red

c) Becomes white

d) Remains the same

18. Which of the following statements is correct for a balanced chemical equation?

a) Total number of atoms may be different on both sides

b) Mass is conserved

c) Atoms are destroyed

d) New elements are formed

19. Which is an example of an exothermic reaction?

a) Decomposition of AgCl in sunlight

b) Dissolution of ammonium chloride

c) Burning of coal

d) Electrolysis of water

20. What does a downward arrow (↓) 

indicate in a chemical equation?

a) Formation of a gas

b) Formation of a precipita

te

c) Evolution of heat

d) Reaction is reversible