Question

Describe how the following changes are brought about:
Impure titanium into pure titanium.

Answer 1

Impure titanium is heated with iodine to form volatile $Ti{l}_4$, which decomposes on tungsten filament at high temperature to give pure titanium.
$\underset{Impure}{Ti\left(s\right)}+2I_2\left(g\right)\stackrel{523K}{\to }Ti{I}_4\left(g\right)\stackrel{1700K}{\to }\underset{Pure}{Ti\left(s\right)}+2I_2\left(g\right)$.