Question

The method used in metallurgy to refine the impure metal is:

• A. Mond process
• B. Van Arkel process
• C. Liquation
• D. All of the above

Answer 1

The correct option is D All of the above

$\text{Mond Method:}$ It is specially used for Ni. The vapour phase refining of Ni on heating in a stream of CO forms volatile $Ni(CO{)}_4$. These vapours when subjected to still higher temperature, decompose to give pure metal.

$\text{Liquation Method:}$ Pb, Sn, Bi, Zn etc are purified by this method. The metal has a low melting point and impurities have a high melting point. In an open hearth, the metal is heated to its melting point and metal melts down and impurities remain behind.

$\text{Van Arkel method}$: This method is used for ultrapure metals like Ti, Zr etc. The metal is converted into its volatile stable compound such as $Ti{I}_4$, leaving behind impurities. The stable volatile compound thus formed is decomposed to get the pure metal.

Hence, option D is correct.