Assertion (A) : A piece of Zinc metal gets reddish brown coating when kept in copper sulphate solution for some time. Reason (R) : Copper is more reactive metal than Zinc.
Generated by claude-sonnet-4-6 · 2026-06-15 06:49 · grounding rag
Model Answer
Option (C): (A) is true, but (R) is false.
Assertion is true — Zinc displaces copper from copper sulphate solution, forming a reddish-brown copper coating: $\text{Zn} + \text{CuSO}_4 \rightarrow \text{ZnSO}_4 + \text{Cu}$. But Reason is false — Zinc is more reactive than copper, not less.
Source: Chemical Reactions and Equations, Section 1.2.3; Metals and Non-metals, Section 3.2.5
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Explanation
- The Assertion describes a displacement reaction — Zinc (being more reactive) displaces copper from CuSO₄, depositing reddish-brown copper on the zinc piece. This is true.
- The Reason states copper is more reactive than zinc — this is false. The reactivity series clearly places Zn above Cu, meaning Zn is more reactive.
- Since A is true but R is false, the answer is (C).
- Examiners expect you to state both the correct option and a brief justification referencing the reactivity series.