Question

You are provided with samples of some impure metals such as zinc, copper and germanium. Describe the methods you recommend for the purification of each of these metals.

Answer 1

1. Zinc: It is purified by distillation, as zinc has a low boiling point and distils away from non-volatile impurities.
2. Copper: It is purified by electrolytic refining using CuSO₄ solution, where pure copper is deposited at the cathode and impurities form anode mud.
3. Germanium: It is purified by zone refining, in which impurities are swept to one end of the rod by a moving heater, leaving behind ultra-pure germanium.