Question

Describe a method for refining nickel.

Answer 1

Mond’s process refines nickel. In this process, nickel is heated in the presence of carbon monoxide to form nickel tetracarbonyl, a volatile complex.

$$\mathrm{Ni}+4\mathrm{CO}\stackrel{330-350\mathrm{K}}{\to }\underset{\mathrm{Nickel}\mathrm{tetracarbonyl}}{\mathrm{Ni}(\mathrm{CO}){\phantom{A}}_4}$$

Then, the obtained nickel tetracarbonyl is decomposed by subjecting it to a higher temperature (450 − 470 K) to obtain pure nickel metal.

$$\underset{\mathrm{tetracarbonyl}}{\underset{\mathrm{Nickel}}{\mathrm{Ni}(\mathrm{CO}){\phantom{A}}_4}}\stackrel{450-470\mathrm{K}}{\to }\underset{\mathrm{Nickel}}{\mathrm{Ni}}+4\mathrm{CO}$$