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Chemical Reactions & Equations – MCQs
Class 10 (HSLC )

1. Which of the following is a chemical reaction?
a) Melting of ice
b) Dissolving sugar in water
c) Rusting of iron
d) Breaking of glass

Answer: c) Rusting of iron

2. The reaction in which heat is absorbed is called:
a) Exothermic reaction
b) Endothermic reaction
c) Displacement reaction
d) Combination reaction

Answer: b) Endothermic reaction

3. Which type of reaction is:
CaO + H₂O → Ca(OH)₂ ?
a) Decomposition
b) Displacement
c) Combination
d) Double displacement

Answer: c) Combination

4. Which gas is released when zinc reacts with dilute hydrochloric acid?
a) Oxygen
b) Hydrogen
c) Carbon dioxide
d) Nitrogen

Answer: b) Hydrogen

5. The balanced chemical equation for burning of magnesium is:
a) Mg + O₂ → MgO
b) 2Mg + O₂ → 2MgO
c) Mg₂ + O₂ → MgO
d) Mg + O → MgO

Answer: b) 2Mg + O₂ → 2MgO

6. Which of the following is a displacement reaction?
a) AgNO₃ + NaCl → AgCl + NaNO₃
b) CaCO₃ → CaO + CO₂
c) Zn + CuSO₄ → ZnSO₄ + Cu
d) HCl + NaOH → NaCl + H₂O

Answer: c) Zn + CuSO₄ → ZnSO₄ + Cu

7. Rusting of iron is an example of:
a) Reduction
b) Oxidation
c) Displacement
d) Neutralisation

Answer: b) Oxidation

8. Which substance gets oxidised in the reaction:
Zn + CuO → ZnO + Cu ?
a) Zn
b) CuO
c) Cu
d) ZnO

Answer: a) Zn

9. Which reaction takes place when electricity is passed through water?
a) Combination
b) Displacement
c) Decomposition
d) Double displacement

Answer: c) Decomposition

10. The chemical reaction in which exchange of ions occurs is called:
a) Combination reaction
b) Decomposition reaction
c) Displacement reaction
d) Double displacement reaction

Answer: d) Double displacement reaction

11. Which of the following prevents rusting?
a) Painting
b) Galvanisation
c) Oiling
d) All of the above

Answer: d) All of the above

12. The reaction that releases energy in the form of heat is:
a) Endothermic
b) Exothermic
c) Decomposition
d) Redox

Answer: b) Exothermic

13. Which of the following is a redox reaction?
a) NaCl + AgNO₃ → AgCl + NaNO₃
b) CaCO₃ → CaO + CO₂
c) CuO + H₂ → Cu + H₂O
d) HCl + NaOH → NaCl + H₂O

Answer: c) CuO + H₂ → Cu + H₂O

14. In corrosion of iron, the colour of rust is:
a) Black
b) Brownish red
c) Green
d) White

Answer: b) Brownish red

15. Which symbol is used to show evolution of gas in a chemical equation?
a) ↓
b) ↑
c) →
d) +

Answer: b) ↑

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