Question

The method of zone refining of metals is based on the principle of:
[1 mark]

• A. Greater mobility of the pure metal than that of the impurity
• B. Higher melting point of the impurity than that of the pure metal
• C. Higher melting point of the solid metal than that of the impurity
• D. Greater solubility of the impurity in the molten state than in the solid state

Answer 1

The correct option is D Greater solubility of the impurity in the molten state than in the solid state

Elements which are generally used as semiconductors such as Si, Ge, Ga, etc. are refined by this method, which is based on the difference in solubility of impurities in molten and solid state of the metal.