JAMB Chemistry 2018 Paper

Concept:In the electrolysis of molten sodium chloride, anions move to the anode and are oxidized, while cations move to the cathode and are reduced.Explanation:Molten $\mathrm{NaCl}$ dissociates into $\mathrm{Na}^+$ and $\mathrm{Cl}^-$ ions.At the anode, $\mathrm{Cl}^-$ ions lose electrons and are oxidized to chlorine gas: $2\mathrm{Cl}^- \rightarrow \mathrm{Cl}_2 + 2e^-$.At the cathode, $\mathrm{Na}^+$ ions gain electrons and are reduced to sodium metal: $\mathrm{Na}^+ + e^- \rightarrow \mathrm{Na}$.The electrode labelled Z is the electrode where chlorine ions are oxidized.Therefore, Z is the anode.Answer:A. anode where the $\mathrm{Cl}^-$ ions are oxidized.