The metals produced by various reduction processes are not very pure. They contain impurities, which must be…
The metals produced by various reduction processes are not very pure. They contain impurities, which must be removed to obtain pure metals. The most widely used method for refining impure metals is electrolytic refining.
(i) What is the cathode and anode made of in the refining of copper by this process ?
(ii) Name the solution used in the above process and write its formula.
(iii) (A) How copper gets refined when electric current is passed in the electrolytic cell ?
Solution
(i) Cathode – Pure copper
Anode – Impure copper
(ii) Acidified Copper Sulphate; CuSO4
(iii)(A) Pure copper from the anode dissolves into electrolyte and an equivalent amount of pure metal from the electrolyte is deposited on cathode /
At anode: Cu → Cu++ + 2e-
At cathode: Cu++ + 2e→ Cu (Pure)
The soluble impurities go into the solution whereas insoluble impurities settle down at the bottom of the anode.
[Note: Award marks if explained with a suitable labelled diagram]