Science (086) — AI-generated practice question

Observation 1: When iron filings are added to copper sulphate solution, the blue colour of the solution fades and a reddish-brown deposit of copper is formed on the iron. The reaction is:
$$\text{Fe}(s) + \text{CuSO}_4(aq) \rightarrow \text{FeSO}_4(aq) + \text{Cu}(s)$$

Observation 2: When copper pieces are added to iron sulphate solution, no reaction occurs — there is no change in the colour of the solution and no deposit is formed.

Conclusion: Iron displaces copper from copper sulphate solution, but copper cannot displace iron from iron sulphate solution. This shows that iron is more reactive than copper.

Source: Chapter 1, Section 1.2.3 – Displacement Reaction

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• The key point examiners look for is both observations (one reaction, one no reaction) plus the equation for the first case, and the conclusion about relative reactivity.
• Many students forget to state that copper + FeSO₄ gives no reaction — this is worth marks.
• The logic: a more reactive metal displaces a less reactive one from its salt solution. Since Fe displaces Cu but not vice versa, Fe > Cu in reactivity.