A.Describe the purification of Ti by Van Arkel method. B.Explain the process of purification of Nickel.

Explanation

a. van Arkel process--Vapour phase refining
b.van Arkel process
This method involves thermal decomposition of an unstable compound of the metal. Here the impure metal is, first converted into one of its unstable compounds. This unstable conpound, on heating at higher temperature decomposes to give pure metal. Pure titanium can be obtained from impure titanium by converting it into tetraiodide and then decomposing this tetraiodide to pure titanium.
beginarray/l
Ti+21_2 underset (impure) /longrarr Ti I_4 stackrel2075 ~K/ (Vapour) Fi+2 l_2
(Pure)
endarray
c. see page no 169