What is the electrolytic refining method used for the purification of aluminum called?

Which of the following pairs of metals is purified by the van Arkel method?

Which process of purification is represented by the following equation?
$Ti_{\text{(Impure)}} + 2I_2$ $\xrightarrow{250^{\circ}C} TiI_4$ $\xrightarrow{1400^{\circ}C} Ti_{\text{(Pure)}} + 2I_2$

Explain the purification of metals in the vapour phase with an example.

Mark the variety of iron which has the highest melting point.

Impurities of lead in silver are removed by