Question

What is van arkel method?

Answer 1

Van Arkel method (Vapour Phase Refining )
This method is based on the thermal decomposition of metal components. The process of decompositon of a compound into different substances due to the supply of heat is called thermal decomposition.

Titanium metal is purified by this method. When the impure titanium metal is heated with iodine at a temperature of 2500 C, volatile titanium tetra-iodide is formed (TiI4). The impurities are left behind, as they do not react with iodine.
The titanium tetra-iodide vapour is passed over a hot tungsten filament at 14000 C. The vapour is decomposed and pure titanium is deposited on the filament and is removed. The iodine is reused.
Ti + 2I2 2500C
-------> TiI4
Titanium tetra-iodide

TiI4 14000C
-----------> Ti + 2I2
Tungsten
filament metal

Answer 2

Hey !!

                  VAN ARKEL METHOD        

Small amounts of very pure titanium or zirconium metal can be prepared by this method. Impure metal is heated is an evacuated vessel with I₂. Til₄ is formed which vaporizes leaving behind impurities. The gaseous MI₄ decomposes on a white hot tungsten filament.

        Zr + 2I₂(Impure) --(870K)--> Zr + 2I₂ (Pure)

        Ti + 2I₂(Impure) - (523K)--> TiI₄ + 2I₂ (Pure)

GOOD LUCK !!