NCERT Book Class 10th SCIENCE Chapter 1 Chemical Reactions and Equations MCQ
NCERT Book class 10th SCIENCE MCQ
Chapter 1 : Chemical Reactions and Equations
1. Which of the following is an example of a physical change?
a) Rusting of iron
b) Burning of a candle
c) Melting of ice
d) Souring of milk
Answer: c) Melting of ice
2. What remains conserved in a chemical reaction?
a) Mass
b) Energy
c) Molecules
d) Atoms
Answer: a) Mass
3. Which of the following is a balanced chemical equation?
a) H₂ + O₂ → H₂O
b) 2H₂ + O₂ → 2H₂O
c) H₂ + O₂ → 2H₂O
d) 2H₂ + 2O₂ → 2H₂O
Answer: b) 2H₂ + O₂ → 2H₂O
4. Fe + CuSO₄ → FeSO₄ + Cu is what type of reaction?
a) Combination
b) Displacement
c) Decomposition
d) Neutralization
Answer: b) Displacement
5. CaO + H₂O → Ca(OH)₂ is what type of reaction?
a) Exothermic
b) Endothermic
c) Reversible
d) Decomposition
Answer: a) Exothermic
6. Which of the following is an example of an oxidation reaction?
a) 2Cu + O₂ → 2CuO
b) CuO + H₂ → Cu + H₂O
c) NaCl + AgNO₃ → AgCl + NaNO₃
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2Cu + O₂ → 2CuO
7. A reaction in which oxygen is added is called:
a) Reduction
b) Oxidation
c) Neutralization
d) Displacement
Answer: b) Oxidation
8. Which of the following is an example of a precipitation reaction?
a) 2H₂ + O₂ → 2H₂O
b) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
c) CaCO₃ → CaO + CO₂
d) Zn + H₂SO₄ → ZnSO₄ + H₂
Answer: b) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
9. Which of the following is an example of a combination reaction?
a) 2H₂O → 2H₂ + O₂
b) C + O₂ → CO₂
c) Fe + CuSO₄ → FeSO₄ + Cu
d) NaOH + HCl → NaCl + H₂O
Answer: b) C + O₂ → CO₂
10. The reaction in which an acid and a base react to form salt and water is called:
a) Oxidation
b) Neutralization
c) Displacement
d) Decomposition
Answer: b) Neutralization
11. Which of the following is an example of a decomposition reaction?
a) 2H₂ + O₂ → 2H₂O
b) CaCO₃ → CaO + CO₂
c) Zn + H₂SO₄ → ZnSO₄ + H₂
d) NaOH + HCl → NaCl + H₂O
Answer: b) CaCO₃ → CaO + CO₂
12. What is the purpose of balancing a chemical equation?
a) To satisfy the law of conservation of mass
b) To increase the number of reactants and products
c) To increase the speed of the reaction
d) To control the temperature
Answer: a) To satisfy the law of conservation of mass
13. Which of the following is not a chemical change?
a) Rusting of iron
b) Curdling of milk
c) Burning of paper
d) Conversion of water into steam
Answer: d) Conversion of water into steam
14. Which of the following is an example of an exothermic reaction?
a) CaCO₃ → CaO + CO₂
b) N₂ + O₂ → 2NO
c) C + O₂ → CO₂
d) H₂O → H₂ + O₂
Answer: c) C + O₂ → CO₂
15. What is the role of a catalyst in a chemical reaction?
a) To increase the reaction rate
b) To stop the reaction
c) To increase the amount of products
d) To decrease the temperature
Answer: a) To increase the reaction rate
16. Which of the following is a redox reaction?
a) NaCl + AgNO₃ → AgCl + NaNO₃
b) 2Na + Cl₂ → 2NaCl
c) NaOH + HCl → NaCl + H₂O
d) CaCO₃ → CaO + CO₂
Answer: b) 2Na + Cl₂ → 2NaCl
17. Which of the following is an example of a displacement reaction?
a) 2H₂ + O₂ → 2H₂O
b) Zn + CuSO₄ → ZnSO₄ + Cu
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: b) Zn + CuSO₄ → ZnSO₄ + Cu
18. Which of the following is an example of a decomposition reaction?
a) 2H₂O → 2H₂ + O₂
b) C + O₂ → CO₂
c) Fe + CuSO₄ → FeSO₄ + Cu
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2H₂O → 2H₂ + O₂
19. Which of the following is an example of a combustion reaction?
a) CH₄ + 2O₂ → CO₂ + 2H₂O
b) CaO + H₂O → Ca(OH)₂
c) Zn + H₂SO₄ → ZnSO₄ + H₂
d) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
Answer: a) CH₄ + 2O₂ → CO₂ + 2H₂O
20. Which of the following is an example of a neutralization reaction?
a) NaOH + HCl → NaCl + H₂O
b) 2H₂ + O₂ → 2H₂O
c) CaCO₃ → CaO + CO₂
d) Zn + H₂SO₄ → ZnSO₄ + H₂
Answer: a) NaOH + HCl → NaCl + H₂O
21. Which of the following chemical equations is not balanced?
a) 2Mg + O₂ → 2MgO
b) N₂ + 3H₂ → 2NH₃
c) 2KClO₃ → 2KCl + 3O₂
d) P₄ + 5O₂ → P₂O₅
Answer: d) P₄ + 5O₂ → P₂O₅ (Balanced form: P₄ + 5O₂ → 2P₂O₅)
22. Which of the following is a chemical change?
a) Melting of ice
b) Melting of iron
c) Rusting of iron
d) Boiling of water
Answer: c) Rusting of iron
23. Which of the following is an example of an endothermic reaction?
a) CaO + H₂O → Ca(OH)₂
b) C + O₂ → CO₂
c) 2HgO → 2Hg + O₂
d) CH₄ + 2O₂ → CO₂ + 2H₂O
Answer: c) 2HgO → 2Hg + O₂
24. Which of the following chemical equations is balanced?
a) Fe + H₂O → Fe₃O₄ + H₂
b) 3Fe + 4H₂O → Fe₃O₄ + 4H₂
c) Fe + 2H₂O → FeO + 2H₂
d) 2Fe + 3H₂O → Fe₂O₃ + 3H₂
Answer: b) 3Fe + 4H₂O → Fe₃O₄ + 4H₂
25. Which of the following is a combination reaction?
a) 2H₂O → 2H₂ + O₂
b) 2Na + Cl₂ → 2NaCl
c) CaCO₃ → CaO + CO₂
d) Zn + H₂SO₄ → ZnSO₄ + H₂
Answer: b) 2Na + Cl₂ → 2NaCl
26. In which of the following reactions is oxygen lost?
a) Oxidation
b) Reduction
c) Neutralization
d) Displacement
Answer: b) Reduction
27. Which of the following chemical reactions releases a gas?
a) Zn + H₂SO₄ → ZnSO₄ + H₂
b) NaOH + HCl → NaCl + H₂O
c) CaO + H₂O → Ca(OH)₂
d) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
Answer: a) Zn + H₂SO₄ → ZnSO₄ + H₂
28. Which of the following chemical equations is not balanced?
a) 2KClO₃ → 2KCl + 3O₂
b) 2Al + 3CuCl₂ → 2AlCl₃ + 3Cu
c) 2Fe + 3Cl₂ → 2FeCl₃
d) Mg + O₂ → MgO
Answer: d) Mg + O₂ → MgO (Balanced form: 2Mg + O₂ → 2MgO)
29. Which of the following chemical reactions involves a color change?
a) Fe + CuSO₄ → FeSO₄ + Cu
b) NaOH + HCl → NaCl + H₂O
c) CaCO₃ → CaO + CO₂
d) 2H₂ + O₂ → 2H₂O
Answer: a) Fe + CuSO₄ → FeSO₄ + Cu
30. In which of the following reactions is heat produced?
a) Exothermic
b) Endothermic
c) Reversible
d) None of these
Answer: a) Exothermic
31. Which of the following reactions forms a solid precipitate?
a) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
b) NaOH + HCl → NaCl + H₂O
c) CaO + H₂O → Ca(OH)₂
d) Zn + H₂SO₄ → ZnSO₄ + H₂
Answer: a) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
32. Which of the following reactions produces water?
a) Neutralization
b) Combination
c) Displacement
d) Decomposition
Answer: a) Neutralization
33. In which of the following reactions is energy absorbed?
a) Exothermic
b) Endothermic
c) Reversible
d) None of these
Answer: b) Endothermic
34. Which of the following reactions involves the displacement of a metal?
a) Zn + CuSO₄ → ZnSO₄ + Cu
b) NaOH + HCl → NaCl + H₂O
c) CaCO₃ → CaO + CO₂
d) 2H₂ + O₂ → 2H₂O
Answer: a) Zn + CuSO₄ → ZnSO₄ + Cu
35. Which of the following reactions releases CO₂ gas?
a) CaCO₃ → CaO + CO₂
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) NaOH + HCl → NaCl + H₂O
d) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
Answer: a) CaCO₃ → CaO + CO₂
36. Which of the following reactions produces H₂ gas?
a) Zn + H₂SO₄ → ZnSO₄ + H₂
b) NaOH + HCl → NaCl + H₂O
c) CaO + H₂O → Ca(OH)₂
d) 2H₂ + O₂ → 2H₂O
Answer: a) Zn + H₂SO₄ → ZnSO₄ + H₂
37. Which of the following reactions releases oxygen gas?
a) 2KClO₃ → 2KCl + 3O₂
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) NaOH + HCl → NaCl + H₂O
d) CaO + H₂O → Ca(OH)₂
Answer: a) 2KClO₃ → 2KCl + 3O₂
38. Which of the following reactions involves an acid and a base?
a) Neutralization
b) Combination
c) Displacement
d) Decomposition
Answer: a) Neutralization
39. Which of the following reactions involves two compounds reacting to form new compounds?
a) Double displacement
b) Combination
c) Displacement
d) Decomposition
Answer: a) Double displacement
40. Which of the following reactions involves a single compound breaking into two or more substances?
a) Combination
b) Displacement
c) Decomposition
d) Neutralization
Answer: c) Decomposition
41. Which of the following reactions involves the reduction of a metal oxide?
a) ZnO + C → Zn + CO
b) CaO + H₂O → Ca(OH)₂
c) 2H₂ + O₂ → 2H₂O
d) NaOH + HCl → NaCl + H₂O
Answer: a) ZnO + C → Zn + CO
42. Which of the following reactions involves the oxidation of hydrogen?
a) 2H₂ + O₂ → 2H₂O
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2H₂ + O₂ → 2H₂O
43. Which of the following reactions involves the oxidation of carbon?
a) C + O₂ → CO₂
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaO + H₂O → Ca(OH)₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) C + O₂ → CO₂
44. Which of the following reactions involves the oxidation of iron?
a) 4Fe + 3O₂ → 2Fe₂O₃
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) 4Fe + 3O₂ → 2Fe₂O₃
45. Which of the following reactions involves the reduction of copper?
a) CuO + H₂ → Cu + H₂O
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) CuO + H₂ → Cu + H₂O
46. Which of the following reactions involves the oxidation of magnesium?
a) 2Mg + O₂ → 2MgO
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2Mg + O₂ → 2MgO
47. Which of the following reactions involves the oxidation of sulfur?
a) S + O₂ → SO₂
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) S + O₂ → SO₂
48. Which of the following reactions involves the reduction of nitrogen?
a) N₂ + 3H₂ → 2NH₃
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) N₂ + 3H₂ → 2NH₃
49. Which of the following reactions involves the oxidation of chlorine?
a) Cl₂ + H₂ → 2HCl
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) Cl₂ + H₂ → 2HCl
50. Which of the following reactions involves the decomposition of iron sulfate?
a) 2FeSO₄ → Fe₂O₃ + SO₂ + SO₃
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2FeSO₄ → Fe₂O₃ + SO₂ + SO₃
25 Important MCQs with Answers (CBSE & MP Board Previous Year Questions Included)
1. Which of the following is a physical change?
a) Rusting of iron
b) Burning of a candle
c) Melting of ice
d) Souring of milk
Answer: c) Melting of ice
(CBSE 2020)
2. Which law remains conserved in a chemical reaction?
a) Law of conservation of mass
b) Law of conservation of volume
c) Law of conservation of density
d) Law of conservation of temperature
Answer: a) Law of conservation of mass
(MP Board 2019)
3. Which of the following is a balanced chemical equation?
a) H₂ + O₂ → H₂O
b) 2H₂ + O₂ → 2H₂O
c) H₂ + 2O₂ → H₂O
d) H₂ + O₂ → 2H₂O
Answer: b) 2H₂ + O₂ → 2H₂O
(CBSE 2019)
4. Fe + CuSO₄ → FeSO₄ + Cu is what type of reaction?
a) Combination
b) Displacement
c) Decomposition
d) Neutralization
Answer: b) Displacement
(MP Board 2020)
5. CaO + H₂O → Ca(OH)₂ is what type of reaction?
a) Exothermic
b) Endothermic
c) Neutralization
d) Decomposition
Answer: a) Exothermic
(CBSE 2021)
6. Which of the following is an oxidation reaction?
a) 2Cu + O₂ → 2CuO
b) CuO + H₂ → Cu + H₂O
c) NaCl + AgNO₃ → AgCl + NaNO₃
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2Cu + O₂ → 2CuO
(MP Board 2018)
7. Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃ is what type of reaction?
a) Precipitation
b) Combination
c) Displacement
d) Oxidation
Answer: a) Precipitation
(CBSE 2022)
8. Which of the following is a combination reaction?
a) 2H₂O → 2H₂ + O₂
b) C + O₂ → CO₂
c) Fe + CuSO₄ → FeSO₄ + Cu
d) CaCO₃ → CaO + CO₂
Answer: b) C + O₂ → CO₂
(MP Board 2021)
9. NaOH + HCl → NaCl + H₂O is what type of reaction?
a) Neutralization
b) Displacement
c) Oxidation
d) Decomposition
Answer: a) Neutralization
(CBSE 2020)
10. 2KClO₃ → 2KCl + 3O₂ is what type of reaction?
a) Decomposition
b) Combination
c) Displacement
d) Neutralization
Answer: a) Decomposition
(MP Board 2019)
11. Which of the following is an endothermic reaction?
a) CaO + H₂O → Ca(OH)₂
b) C + O₂ → CO₂
c) 2HgO → 2Hg + O₂
d) CH₄ + 2O₂ → CO₂ + 2H₂O
Answer: c) 2HgO → 2Hg + O₂
(CBSE 2021)
12. In Zn + H₂SO₄ → ZnSO₄ + H₂, which gas is produced?
a) O₂
b) H₂
c) CO₂
d) Cl₂
Answer: b) H₂
(MP Board 2020)
13. Which of the following is a redox reaction?
a) NaCl + AgNO₃ → AgCl + NaNO₃
b) 2Na + Cl₂ → 2NaCl
c) NaOH + HCl → NaCl + H₂O
d) CaCO₃ → CaO + CO₂
Answer: b) 2Na + Cl₂ → 2NaCl
(CBSE 2019)
14. Which of the following is a combustion reaction?
a) CH₄ + 2O₂ → CO₂ + 2H₂O
b) CaO + H₂O → Ca(OH)₂
c) Zn + H₂SO₄ → ZnSO₄ + H₂
d) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
Answer: a) CH₄ + 2O₂ → CO₂ + 2H₂O
(MP Board 2021)
15. What is the purpose of balancing a chemical equation?
a) To satisfy the law of conservation of mass
b) To speed up the reaction
c) To increase the product yield
d) To control temperature
Answer: a) To satisfy the law of conservation of mass
(CBSE 2022)
16. Which of the following is not a chemical change?
a) Rusting of iron
b) Burning of paper
c) Conversion of water into steam
d) Curdling of milk
Answer: c) Conversion of water into steam
(MP Board 2018)
17. In 2Mg + O₂ → 2MgO, what happens to Mg?
a) Oxidation
b) Reduction
c) Neutralization
d) Displacement
Answer: a) Oxidation
(CBSE 2020)
18. In CuO + H₂ → Cu + H₂O, what happens to CuO?
a) Oxidation
b) Reduction
c) Neutralization
d) Displacement
Answer: b) Reduction
(MP Board 2019)
19. Which of the following is a precipitation reaction?
a) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃
(CBSE 2021)
20. Which of the following is a displacement reaction?
a) Zn + CuSO₄ → ZnSO₄ + Cu
b) 2H₂ + O₂ → 2H₂O
c) CaCO₃ → CaO + CO₂
d) NaOH + HCl → NaCl + H₂O
Answer: a) Zn + CuSO₄ → ZnSO₄ + Cu
(MP Board 2020)
21. Which of the following is a combination reaction?
a) 2Na + Cl₂ → 2NaCl
b) 2H₂O → 2H₂ + O₂
c) CaCO₃ → CaO + CO₂
d) Zn + H₂SO₄ → ZnSO₄ + H₂
Answer: a) 2Na + Cl₂ → 2NaCl
(CBSE 2019)
22. Which of the following is a decomposition reaction?
a) 2H₂O → 2H₂ + O₂
b) C + O₂ → CO₂
c) Fe + CuSO₄ → FeSO₄ + Cu
d) NaOH + HCl → NaCl + H₂O
Answer: a) 2H₂O → 2H₂ + O₂
(MP Board 2021)
23. Which of the following is a neutralization reaction?
a) NaOH + HCl → NaCl + H₂O
b) 2H₂ + O₂ → 2H₂O
c) CaCO₃ → CaO + CO₂
d) Zn + H₂SO₄ → ZnSO₄ + H₂
Answer: a) NaOH + HCl → NaCl + H₂O
(CBSE 2022)
24. Which of the following is an exothermic reaction?
a) C + O₂ → CO₂
b) 2HgO → 2Hg + O₂
c) CaCO₃ → CaO + CO₂
d) N₂ + O₂ → 2NO
Answer: a) C + O₂ → CO₂
(MP Board 2018)
25. In which of the following reactions is CO₂ gas released?
a) CaCO₃ → CaO + CO₂
b) Zn + H₂SO₄ → ZnSO₄ + H₂
c) NaOH + HCl → NaCl + H₂O
d) 2H₂ + O₂ → 2H₂O
Answer: a) CaCO₃ → CaO + CO₂
(CBSE 2020)