JAMB Chemistry 2021 Paper

Concept:A more reactive metal displaces a less reactive metal from its salt solution.Explanation:Copper sulphate solution contains $\mathrm{Cu}^{2+}$ ions.To recover copper, the metal added must be higher than copper in the electrochemical series.Iron is more reactive than copper, so it donates electrons and reduces $\mathrm{Cu}^{2+}$ to copper metal.The equation is: $\mathrm{Fe(s) + CuSO_4(aq) \rightarrow FeSO_4(aq) + Cu(s)}$.Ionic form: $\mathrm{Fe(s) + Cu^{2+}(aq) \rightarrow Fe^{2+}(aq) + Cu(s)}$.Sodium reacts violently with water instead of displacing copper.Silver and mercury are less reactive than copper, so they cannot displace it.Therefore, iron is the correct metal for this recovery.Answer:D. Fe