Poling process is used for

Which one of the following methods can be used to obtain highly pure metal which is liquid at room temperature?

Copper sulphate is prepared by blowing a current of air through copper scrap and dilute $H_2SO_4$. Dilute $HNO_3$ is also added:

Choose the correct option for vapor phase refining.
$A :$ The metal should form a volatile compound with an appropriate reagent.
$R :$ The volatile compound obtained should be easily decomposable.

Match the following items of List-$I$ with those of List-$II$:

List-$I$	List-$II$
$(A)$ Nickel	$(1)$ Electrolytic refining
$(B)$ Titanium	$(2)$ Zone refining
$(C)$ Germanium	$(3)$ van-Arkel method
$(D)$ Copper	$(4)$ Mond process

The correct answer is:

During the process of electrolytic refining of copper,some metals present as impurity settle as 'anode mud'. These are