Which one of the following principle has been used in the zone melting method?
A
Impurities concentrate in the liquid phase than in gaseous phase
B
Impurities concentrate in the solid than in liquid phase
C
Impurities concentrate in the gaseous phase than in the solid phase
D
Impurities concentrate in the liquid phase than in the solid phase
Answer:
The correct option is D. Impurities concentrate in the liquid phase than in the solid phase
Note
Zone melting method make the use of the principle that impurities usually concentrate in the liquid rather than in the solid phase. Impurities are therefore ‘swept out’ of the crystal by the moving molten zone. The method has been used for the purification and crystal growth of the high melting metals such as tungsten.