Iron nails are immersed in copper sulphate solution. After some time, the blue colour of the solution begins to fade. What type of chemical reaction is taking place? Identify the substance that gets displaced in this reaction and give a reason for your answer.
Generated by claude-sonnet-4-6 · 2026-06-26 00:53 · grounding rag
Model Answer
This is a displacement reaction.
Copper ($\text{Cu}$) is the substance that gets displaced.
Reaction: $\text{Fe}(s) + \text{CuSO}_4(aq) \rightarrow \text{FeSO}_4(aq) + \text{Cu}(s)$
Iron displaces copper because iron is more reactive than copper. It removes copper from copper sulphate solution, forming iron sulphate; hence the blue colour of the solution fades.
Source: Chapter 1, Section 1.2.3 – Displacement Reaction
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Explanation
- 1 mark for correctly naming the reaction type (displacement reaction).
- 1 mark for identifying copper as the displaced substance AND giving the reason (iron is more reactive than copper).
- Writing the balanced equation is a strong supporting point and shows clarity — examiners appreciate it even if not explicitly demanded.
- Do not say iron is displaced; iron does the displacing, copper is displaced.