Science (086) — AI-generated practice question

This is a displacement reaction.

Chemical equation:
$$\text{Fe}(s) + \text{CuSO}_4(aq) \rightarrow \text{FeSO}_4(aq) + \text{Cu}(s)$$

Reason for colour change: Iron is more reactive than copper, so it displaces copper from copper sulphate solution. The blue colour of copper sulphate (CuSO₄) gradually fades because it is converted into iron sulphate (FeSO₄), which is pale green/colourless. Copper gets deposited on the iron nail, turning it brownish.

Source: Chapter 1, Section 1.2.3 – Displacement Reaction

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• 1 mark for naming the reaction type (displacement reaction).
• 1 mark for the balanced chemical equation.
• 1 mark for the reason — iron displaces copper because it is more reactive; CuSO₄ (blue) is converted to FeSO₄ (colourless/pale green), causing the blue colour to fade.
• Always write the chemical equation in a displacement reaction answer — examiners expect it.
• Don't forget to mention why the colour fades (the product FeSO₄ is not blue).