Question

Name two alloys of copper.

From the figure, give the electrode reaction. What is this process called?

Answer 1

(a) Bras: Cu (60%) + Zn (40%)
Bronze: Cu (90%) + Sn (10%)
(b) This process is known as electrolyte refining. The impure metal is used as anode and pure metal is used as cathode. The electrolyte is a solution of a suitable salt of the metal. On passing electric current, the pure metal is deposited on the cathode. The solid impurities fall to the bottom of the cell and are recovered as anode mud. The soluble impurities go to the solution. For the purification of copper sulphate and the electrode reactions are
Anode: Cu → Cu₂ + 2e^-
Cathode: Cu₂ + 2e^- → Cu