Question

(i) Metals can be recovered from their ores by chemical methods.

(ii) High purity metals can be obtained by zone refining method.

Which one is true /false.

• A. (i) is true and (ii) is false
• B. (ii) is true and (i) is false
• C. (i) and (ii) are true
• D. (i) and (ii) are false

Answer 1

The correct option is C (i) and (ii) are true

(i) Many metals occur in nature as oxides, carbonates, sulphides which can be calcined or roasted. Then, they can be further treated chemically to get the metal.
(ii) Elements such as Si, Ge, Ga, etc., which are used as semiconductors, are refined by zone refining method. Highly pure metals arc obtained. The method is based on the difference in solubility of impurities in molten and solid state of the metal. A movable heater is fitted around a rod of the impure metal. The heater is slowly moved across the rod. The metal melts at the point of beating and as the heater moves on from one end of the rod to the other end, the pure metal crystallizes, while the impurities pass on to the adjacent molten zone.