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

Blister copper is refined by stirring molten impure metal with green logs of wood because such wood liberates hydrocarbon gases (like $CH_4$). This process $X$ is called . . . . . . . . . and the metal contains impurities of $Y$ is . . . . . . . . .

The purest zinc is made by

Which process of purification is represented by the following scheme?
$\text{Ti}_{\text{impure}} + 2I_2$ $\xrightarrow{250^{\circ}C} TiI_4$ $\xrightarrow{1400^{\circ}C} \text{Ti}_{\text{pure}} + 2I_2$

The refining method used when the metal and the impurities have low and high melting temperatures,respectively,is

The Van Arkel method for the purification of metals involves converting the metal into a: