Question:
Zone refining is based on the principle that ___________.
(i) impurities of low boiling metals can be separated by distillation.
(ii) impurities are more soluble in molten metal than in solid metal.
(iii) different components of a mixture are differently adsorbed on an absorbent.
(iv) vapours of the volatile compound can be decomposed in pure metal.
Solution:
Option (ii) impurities are more soluble in molten metal than in solid metal is the answer.