The method of electrolytic refining is not suitable in the extraction of

Which of the following properties of pure metal makes it more useful than the corresponding alloy?

The zone refining method is used for the purification of .....

$A$ metal which is refined by poling is

Identify the statements which are not correct.
$a)$ Copper is refined by Van-Arkel method
$b)$ Zinc is refined by electrolysis method
$c)$ Zirconium is refined by distillation method

Which of the following elements is purified by vapour phase refining?