(i) Mond Process for refining of Nickel : The mond process for refining nickel is based on some features. In this process, impure nikel is exposed to carbon monoxide gas at `50^(@)C`. Whereby volatile nikel tetra carbonyl forms. No impurity present in the crude nickel reacts with carbon monoxide e.g.
`underset("Impure")(Ni+4CO)overset(330-350K)rarrunderset("Tetra carbonyl nickel")(Ni(CO_(4)))overset(450-470K)rarrunderset("Pure")(Ni+4CO)`
(ii) Column Chromatography : Different components of mixture are absorbed to different extents, depending upon their polarity.
