Question

The purification of alumina is called (a) Baeyer's process (b) Bosch process (c) Castuer process (d) Hoop's process

Answer 1

The purification of aluminium is called :

Baeyer's Process .

ANSWER :

OPTION A

Details :

$\mathfrak{\underline{REACTION}}$

$\sf{Al_2O_3H_2O+2NaOH\rightarrow2NaAlO_2+3H_2O$

The sodium hydroxide is used because it reacts with aluminium .

The impurities do not react.

This is because the impurities are not amphoteric in nature and hence they do not react.

After the step , the sodium aluminate is obtained .

This is converted to aluminium hydroxide and sodium hydroxide is given .

Then aluminium hydroxide is reduced to obtain Aluminium .

$\sf{2Al(OH)_3 \rightarrow Al_2O_3+3H_2O}$

Then electrolytic reduction is done to purify the aluminium .