Ncert Exercises & Solutions

The following method of purification, where metal is converted to its volatile compound that gives pure metal is upon the decomposition :

a. Heating with a stream of carbon monoxide.

b. Heating with iodine.

c. Liquation

d. Distillation

Choose the correct option :

1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

HINT: Mond's process and van Arkel method.

Explanation:

Vapour phase refining method includes.

(i) Heating of metal with stream of CO:

Mond process for refining of Nickel is based on the principle that nickel is heated in the presence of carbon monoxide to form nickel tetracarbonyl, which is a volatile complex.

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

Ni + 4 CO \to Ni {(CO)}_{4} \overset{450 - 470 K}{\to} Ni + 4 CO (Mond' s process)

(ii) Heating with iodine:

In this method oxygen and nitrogen, present as impurity are removed by heating metal in an evacuated vessel with iodine.

The metal iodide volatize and it is decomposed on a tungsten filament, heated to about 1800K. The pure metal is deposited on the filament.

Zr + 2 I_{2} \overset{870 K}{\to} {ZrI}_{4} \overset{2075 K}{\to} Zr + 2 I_{2} (van Arkel method)

NEET Information

courses

Company

Botany Questions

Chemistry Questions

Physics Questions

Zoology Questions