Question

Electrolytic purification of copper is required since the product of the Bessemer converter is impure. Sheets of pure copper are made the cathodes and blister copper is used as the anodes. The bath contains $CuS{O}_4$, $H_{2}S{O}_4$ and $NaCl$. Metallic copper goes into solution as $C{u}^{+2}$ ions at the anode and deposited at the cathode. Zinc and iron go into solution and do not deposit at the cathode along with copper. Silver goes into solution as $A{g}^{+}$ ions, but forms a sludge in the electrolysis cell. The noble metals such as gold and platinum do not dissolve; they fall to the bottom when released from the copper anode. They help to pay for the copper refining process.
The voltage is kept low enough during the operation. This is to ensure that

• A. $F{e}^{+2}$ and $Z{n}^{+2}$ ions are kept in solution only
• B. there is no risk of electric shock to the plant operators
• C. gold and platinum do not dissolve in solution and are recovered as solids
• D. temperature control is maintained to effect reaction rate control

Answer 1

Answer: (A)

Increasing voltage would cause deposition of $F{e}^{+2}$ and $Z{n}^{+2}$ also to occur.