Purification of aluminium done by electrolytic refining is known as

The extraction of nickel involves:

Match the following:
| List-$I$ (Refining Methods) | List-$II$ (Metal to be refined) |
| :--- | :--- |
| $(A)$ Zone refining | $(I)$ Titanium |
| $(B)$ Poling | $(II)$ Tin |
| $(C)$ Liquation | $(III)$ Gallium |
| $(D)$ Vapour phase refining | $(IV)$ Copper |

Which element is obtained in the pure form by the Van Arkel method?

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

Refining of tin cannot be done by