Question

Copper is purified by the electrolytic refining of blister copper. The correct statement(s) about this process is/are:

• A. impure Cu strip is used as cathode
• B. acidified aqueous $CuS{O}_4$is used as electrolyte
• C. pure $Cu$ deposits at cathode
• D. impurities settle as anode mud

Answer 1

Answer: (B), (C), (D)

impurities settle as anode mud

Blister copper - the final product obtained in the extraction of copper is still impure!
For instance, this 'blister copper' cannot be directly used in circuitry or to create electrical wires.
It needs further refining.

This is accomplished electrolytically by using an impure strip of copper as an anode. The electrolyte is an
acidified aqueous solution of $CuS{O}_4$. For any cell - Galvanic or electrolytic - at the anode, oxidation happens.

So the cathode is a strip of pure copper. $C{u}^{2+}\left(aq\right)$ gets reduced to pure metallic $Cu\left(s\right)$.
Just below the anode, which is made of impure blister copper, impurities like gold and silver (traces only) settle down
as "anode mud".