Statement I: Electrolysis of CuCl2(aq) gives 1 mole of Cu and 1 mole of by the passage of suitable c — Electrochemistry Chemistry Question

💡 Solution & Explanation

\textbf{Assertion (I):} When aqueous CuCl\textsubscript{2} is electrolysed using inert electrodes, Cu deposits at the cathode and Cl\textsubscript{2} gas is evolved at the anode. \textbf{Reason (II):} Cu\textsuperscript{2+} ions are discharged at the cathode in preference to H\textsubscript{2}O, and Cl\textsuperscript{-} ions are discharged at the anode in preference to OH\textsuperscript{-} ions. \textbf{Analysis:} At the \textbf{cathode} (reduction): Both Cu\textsuperscript{2+} and H\textsubscript{2}O are present. Since E\textdegree(Cu\textsuperscript{2+}/Cu) = +0.34 V is much higher than E\textdegree(H\textsuperscript{+}/H\textsubscript{2}) = 0.00 V, Cu\textsuperscript{2+} is preferentially reduced: \[ \text{Cu}^{2+} + 2e^- \rightarrow \text{Cu} \quad E^\circ = +0.34\ \text{V} \] At the \textbf{anode} (oxidation): Both Cl\textsuperscript{-} and OH\textsuperscript{-} are present. Due to overpotential effects and high Cl\textsuperscript{-} concentration, Cl\textsuperscript{-} is preferentially oxidised: \[ 2\text{Cl}^- \rightarrow \text{Cl}_2 + 2e^- \quad E^\circ = +1.36\ \text{V (lower actual overpotential)} \] Statement II correctly explains the selective discharge mechanism behind Statement I. \textbf{Answer: A}