In electrolytic refining of copper, the electrolyte is a solution of

In electrolytic refining of copper, the electrolyte is a solution of

[amp_mcq option1=”acidified copper chloride.” option2=”acidified copper sulphate.” option3=”potassium chloride.” option4=”sodium sulphate.” correct=”option2″]

This question was previously asked in
UPSC NDA-1 – 2021
In electrolytic refining of copper, the electrolyte is a solution of acidified copper sulphate.
In the process of electrolytic refining, impure copper acts as the anode and dissolves as Cu²⁺ ions, while pure copper acts as the cathode where Cu²⁺ ions from the electrolyte are deposited. The electrolyte needs to contain Cu²⁺ ions, which is achieved by using a solution of copper sulfate (CuSO₄). Sulfuric acid (H₂SO₄) is added to the copper sulfate solution to increase its conductivity and prevent the precipitation of copper hydroxide.
Impurities in the anode that are less reactive than copper (like gold, silver, platinum) settle down as anode mud, while more reactive impurities (like zinc, iron, nickel) dissolve in the electrolyte but do not get deposited on the cathode under controlled voltage.