Metal $X$ obtained from sphalerite ore can be purified by which of the following methods?

Match the following List-$I$ (Method) with List-$II$ (Metal refined):

List-$I$ (Method)	List-$II$ (Metal refined)
$(A)$ Zone refining	$(I)$ $Sn$
$(B)$ Liquation	$(II)$ $In$
$(C)$ Vapour phase refining	$(III)$ $Zn$
$(D)$ Distillation	$(IV)$ $Zr$
-	$(V)$ $Al$

The correct answer is:

Nitriding is a process of heating steel in an atmosphere of

When copper is purified by the electrorefining process,noble metals like $Ag$ and $Au$ are found in:

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 |

Name the process that is employed to refine aluminium.