JAMB Chemistry 2022 Paper

Concept:The electrochemical series lists metals in order of their reactivity and electrode potential.At the cathode, cations with a greater tendency to gain electrons are discharged first.Explanation:In the electrochemical series, metals placed lower in the series are less reactive and have higher reduction potentials.Therefore, their ions are more easily reduced and discharged at the cathode.The series order is: $K > Na > Ca > Mg > Al > Zn > Fe > Sn > Cu$.Among $Cu^{2+}$, $Sn^{2+}$, $Fe^{2+}$, and $Zn^{2+}$, copper is the least reactive metal.So $Cu^{2+}$ has the greatest tendency to be discharged at the cathode.Answer:A. $Cu^{2+}$