(i) Write the role of 'CO' in the purification of nickel.
(ii) What is the role of silica in the extraction of copper ?
(iii) What type of metals are generally extracted by electrolytic method ?
(i) forms a volatile complex Nickel tetracarbonyl,
leaving behind impurities. The nickel tetracarbonyl complex is heated to a higher temperature, decomposes to give pure metal.
(ii) Silica acts as a flux, added before roasting to combine with
[impurity] and form
[slag]
(iii) Very highly reactive metals like sodium, Potassium,calcium etc are generally extracted by electrolytic method.