Question

The process of Zone refining is used in the purification of:
A.Al
B.Ge
C.Cu
D.Ag

Answer 1

Hint- We use zone refining to refine semiconductor metals like silicon (Si), germanium (Ge) to obtain them in their purest form.

Complete step by step answer:
The process mentioned in this question is zone melting. We use the process to get the highly purified form of the element. This method effectively removes impurities from semiconducting elements like silicon, germanium, and gallium.
Among the given options for this question, aluminium (Al), copper (Cu), and silver (Ag) are metals, while germanium (Ge) is a semiconductor. Hence, the correct answer is germanium (Ge).

Additional Information:
We must remember that the zone refining is a technique based on the principle that impurities are more soluble in their corresponding melt state than their solid-state.
It makes use of a circular heater which is placed in an ingot of metal. The place of metal which is at contact with the heater will melt. When the heater shifts to the next zone, the impurities will move along with it while the pure metal cools and gets crystallized.
The heater moves along the block of metal several times and finally the impurities will accumulate at one end and we will get the purified form of the element.
We widely use the purified germanium in the production of semiconductor diodes.

Note: We can also use the zone refining method to purify metals with low melting point like lead and tin. We must understand that this method is applicable to all types of metals where the impurities in the metal are more soluble in the molten state of the solid.