a) Which method would you recommend for the purification of each of these metals? b) Briefly explain each method.

Question

You are provided with samples of some impure metals such as Titanium and Nickel. 

a) Which method would you recommend for the purification of each of these metals?

b) Briefly explain each method.

Answer 1

a) Ti – van Arkel method
Ni – Monds process

b) The crude metal is heated in an evacuated vessel with iodine. The metal iodide is formed. The metal iodide is decomposed on a tungsten filament, at about 1800 K. The pure metal is ’ deposited on the filament.

Mond process: In this method impure Ni is heated in a stream of carbon monoxide forming a volatile complex, nickel tetracarbonyl.

The carbonyl is subjected to higher temperature so that it is decomposed to give pure metal.