In electrorefining of metals,the anode and cathode are taken as a thick slab of impure metal and a strip of pure metal,respectively,while the electrolyte is a solution of a complex metal salt. This method cannot be applied for the refining of:

Given below are two statements.
Statement $I:$ During electrolytic refining,blister copper deposits precious metals.
Statement $II:$ In the process of obtaining pure copper by electrolysis method,blister copper is used to make the anode.
In the light of the above statements,choose the most appropriate answer from the options given below.

If a metal has low oxygen affinity,then the purification of the metal may be carried out by:

The purification of $Zr$ (Zirconium) is carried out by the $Van$ $Arkel$ method. Which halogen is used in this process?

In the Hoope's process for refining of aluminium,the fused materials form three different layers and they remain separated during electrolysis. This is because:

$Si$ and $Ge$ used for semiconductors are required to be of high purity and hence purified by: