Assertion-Reason Type Questions
Q1. Assertion (A): Burning of magnesium ribbon is a physical change.
Reason (R): Magnesium ribbon burns with a dazzling white flame to form
magnesium oxide.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Q2. Assertion (A): In a balanced chemical equation, the total mass of
reactants is equal to the total mass of products.
Reason (R): In a balanced chemical equation, the number of atoms of each
element is conserved.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Q3. Assertion (A): Zinc reacts with dilute hydrochloric acid to form
zinc chloride and hydrogen gas.
Reason (R): Zinc is more reactive than hydrogen and displaces it from
hydrochloric acid.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
Matching Type Questions
Q4. Match the following reactants with their products:
|
Reactants |
Products |
|
(i)
Zinc + Hydrochloric acid |
(a)
Magnesium oxide |
|
(ii)
Magnesium + Oxygen |
(b)
Hydrogen gas + Zinc chloride |
|
(iii)
Lead nitrate + Potassium iodide |
(c)
Lead iodide + Potassium nitrate |
(i) - (b), (ii) - (a), (iii) - (c)
(i) - (a), (ii) - (c), (iii) - (b)
(i) - (c), (ii) - (b), (iii) - (a)
(i) - (b), (ii) - (c), (iii) - (a)
Q5. Match the following types of chemical reactions with their
examples:
|
Column A |
Column B |
|
A)
Combination reaction |
1) CaCO₃ → CaO
+ CO₂ |
|
B)
Decomposition reaction |
2) Mg +
O₂ → MgO |
|
C)
Displacement reaction |
3) Zn +
CuSO₄ → ZnSO₄ + Cu |
|
D)
Double displacement reaction |
4) Na₂SO₄ + BaCl₂ → BaSO₄ +
2NaCl |
A) A-2, B-1, C-3, D-4
B) A-1, B-2, C-3, D-4
C) A-3, B-1, C-2, D-4
D) A-4, B-3, C-2, D-1
Multiple Choice Questions
Q6. What is the chemical formula of magnesium oxide?
(a) MgO
(b) MgO₂
(c) Mg₂O
(d) Mg₂O₃
Q7. Which of the following statements is true for a chemical reaction?
(a) Energy is always absorbed.
(b) Energy is always released.
(c) Energy is neither absorbed nor released.
(d) Energy is either absorbed or released.
Q8. The reaction Zn + H₂SO₄ → ZnSO₄ + H₂ is an example of:
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Redox reaction
Q9. Which of the following observations help to determine whether a
chemical reaction has taken place?
(a) Change in state
(b) Change in colour
(c) Evolution of gas
(d) All of the above
Q10. The reaction 2Mg + O₂ → 2MgO is an example
of:
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Redox reaction
Q11. Which of the following is not a characteristic of a chemical
reaction?
(a) Change in colour
(b) Evolution of gas
(c) Change in temperature
(d) Change in shape
Q12. In the reaction between lead nitrate and potassium iodide, the
precipitate formed is:
(a) Lead iodide
(b) Potassium nitrate
(c) Lead nitrate
(d) Potassium iodide
Q13. Which law states that mass can neither be created nor destroyed in
a chemical reaction?
(a) Law of Conservation of Energy
(b) Law of Conservation of Mass
(c) Law of Multiple Proportions
(d) Law of Definite Proportions
Q14. Which of the following is the correct balanced form of the
equation: Fe + H₂O → Fe₃O₄ + H₂?
(a) Fe + H₂O → Fe₃O₄ + H₂
(b) 3Fe + 4H₂O → Fe₃O₄ + 4H₂
(c) 4Fe + 3H₂O → 2Fe₃O₄ + 3H₂
(d) 2Fe + 3H₂O → Fe₃O₄ + 2H₂
Q15. The equation Zn + HCl → ZnCl₂ + H₂ represents:
(a) A combination reaction
(b) A decomposition reaction
(c) A displacement reaction
(d) A double displacement reaction
Fill in the Blanks
Q16. In the reaction between zinc and hydrochloric acid, zinc ________
hydrogen from the acid.
(a) replaces
(b) adds
(c) absorbs
(d) combines
Q17. The burning of magnesium ribbon in air produces ________.
(a) Magnesium chloride
(b) Magnesium oxide
(c) Magnesium sulphate
(d) Magnesium hydroxide
Q18. A chemical equation is balanced when the number of ________ of
each element is equal on both sides.
(a) molecules
(b) atoms
(c) compounds
(d) ions
Q19. The reaction between lead nitrate and potassium iodide is an
example of a ________ reaction.
(a) combination
(b) decomposition
(c) displacement
(d) double displacement
Q20. During a chemical reaction, energy can be ________.
(a) created
(b) destroyed
(c) absorbed or released
(d) none of these
Answers with Explanation
Q1. (d) A is false, but R is true.
Explanation: Burning of magnesium ribbon is a chemical change, not
a physical change.
Q2. (a) Both A and R are true, and R is the correct explanation of A.
Explanation: The law of conservation of mass states that mass is
conserved in a chemical reaction.
Q3. (a) Both A and R are true, and R is the correct explanation of A.
Explanation: Zinc displaces hydrogen from hydrochloric acid because
it is more reactive.
Q4. (i) - (b), (ii) - (a), (iii) - (c)
Explanation: The products correspond to the given reactants in the
reactions.
Q5. Answer: A) A-2, B-1, C-3, D-4
Explanation: The examples correctly match the types of chemical reactions:
- Combination reaction: Mg +
O₂ → MgO
- Decomposition reaction:
CaCO₃ → CaO + CO₂
- Displacement reaction: Zn +
CuSO₄ → ZnSO₄ + Cu
o Double displacement
reaction: Na₂SO₄ + BaCl₂ → BaSO₄ + 2NaCl
Q6. (a) MgO
Explanation: The chemical formula of magnesium oxide is MgO.
Q7. (d) Energy is either absorbed or released.
Explanation: Chemical reactions involve energy changes which can be
either endothermic or exothermic.
Q8. (c) Displacement reaction
Explanation: Zinc displaces hydrogen in the reaction with sulphuric
acid.
Q9. (d) All of the above
Explanation: All listed observations can indicate a chemical
reaction.
Q10. (a) Combination reaction
Explanation: Two or more substances combine to form a single
product.
Q11. (d) Change in shape
Explanation: Change in shape is not typically a characteristic of a
chemical reaction.
Q12. (a) Lead iodide
Explanation: Lead iodide precipitates out in the reaction between
lead nitrate and potassium iodide.
Q13. (b) Law of Conservation of Mass
Explanation: This law states that mass remains constant in a
chemical reaction.
Q14. (b) 3Fe + 4H₂O → Fe₃O₄ + 4H₂
Explanation: The balanced form of the equation ensures the
conservation of atoms.
Q15. (c) A displacement reaction
Explanation: Zinc displaces hydrogen from hydrochloric acid.
Q16. (a) replaces
Explanation: Zinc replaces hydrogen in the reaction with
hydrochloric acid.
Q17. (b) Magnesium oxide
Explanation: Burning magnesium produces magnesium oxide.
Q18. (b) atoms
Explanation: Balancing chemical equations ensures the same number
of atoms of each element on both sides.
Q19. (d) double displacement
Explanation: Two compounds exchange ions in the reaction between
lead nitrate and potassium iodide.
Q20. (c) absorbed or released
Explanation: Energy is involved in all chemical reactions, either
absorbed or released.
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