Question:medium

What will happen during the electrolysis of aqueous solution of \(CuCl_2\) by using platinum electrodes?

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In electrolysis, reduction happens at the cathode (the species easiest to reduce is discharged) and oxidation happens at the anode (the species easiest to oxidise is discharged).
Updated On: Jun 16, 2026
  • Cu will deposit at Anode
  • \(H_2\) gas will be released at cathode
  • \(O_2\) gas will be released at anode
  • \(Cl_2\) gas will be released at anode
Show Solution

The Correct Option is D

Solution and Explanation

Step 1: Note the electrode and the species present.
Platinum electrodes are inert, so they do not dissolve or take part in the reaction. In aqueous \(CuCl_2\) the species are \(Cu^{2+}\), \(Cl^-\), and water (which can give \(H^+\) and \(OH^-\)).

Step 2: Apply the rule for the cathode.
Reduction happens at the cathode and the species easiest to reduce is discharged. \(Cu^{2+}\) is reduced more easily than \(H^+\) from water, so copper metal deposits at the cathode: \(Cu^{2+} + 2e^- \rightarrow Cu\). So no \(H_2\) is released.

Step 3: Apply the rule for the anode.
Oxidation happens at the anode. The competition is between \(Cl^-\) and water (giving \(O_2\)). Although water has a lower standard discharge potential, the overvoltage for \(O_2\) on platinum is high, so chloride is preferentially oxidised.

Step 4: Write the anode reaction.
\(2Cl^- \rightarrow Cl_2 + 2e^-\), so chlorine gas is released at the anode, not oxygen.

Step 5: Conclude.
Copper deposits at the cathode and chlorine gas is released at the anode. The correct statement is that \(Cl_2\) gas is released at the anode.

\[ \boxed{Cl_2\ \text{gas will be released at anode}} \]
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