In the purification of impure nickel by Mond's process,metal is purified by

Zone refining process is used for which of the following?

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 |

The zone refining method is used for which of the following?

Assertion : Lead,tin and bismuth are purified by liquation method.
Reason : Lead,tin and bismuth have low $m.p.$ as compared to impurities.

$TiI_{4}$ on heating gives