Question

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

Options

• impure Cu strip is used as cathode.

• acidified aqueous CuSO₄ is used as electrolyte.

• pure Cu deposits at cathode.

• impurities settle as anode-mud.

Answer 1

Acidified aqueous CuSO₄ is used as electrolyte, pure Cu deposits at cathode and impurities settle as anode-mud.

Explanation:

In electrolytic refining of blister copper, the impure copper is used as the anode (not cathode). The electrolyte is an acidified aqueous copper sulphate (CuSO₄) solution, which facilitates the flow of copper ions. When electric current passes, copper from the anode dissolves into the electrolyte as Cu²⁺ ions and deposits as pure copper on the cathode. The impurities do not dissolve and settle down as anode mud (or anode sludge) at the bottom of the cell. This process purifies copper effectively by transferring copper ions from the impure anode to the cathode, leaving behind the impurities.