Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite?

Question

Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite? (A) Hydrated Al 2 O 3 precipitates, when CO 2 is bubbled through a solution of sodium aluminate. (B) Addition of Na 3 AlF 6 lowers the melting point of alumina. (C) CO 2 is evolved at the anode during electrolysis. (D) The cathode is a steel vessel with a lining of carbon.

Tardigrade Admin · Accepted Answer

Sodium meta aluminate is precipitated in the form of

A l (O H)_{3}

or

A l_{2} O_{3} \cdot x H_{2} O

.
i.e hydrated aluminium hydroxide by passing

C O_{2}

gas.

2 N a A l O_{2} + C O_{2} (g) + 3 H_{2} O (ℓ) ⟶ O r A l_{2} O_{3} \cdot k H_{2} O 2 A l (O H)_{3} ↓ + N a_{2} C O_{3}

In electrolytic reduction of

A l_{2} O_{3}

by Hall-Haroult process,
cryolite

(N a_{3} A l F_{6})

and fluorspar

(C a F_{2})

are added in order to reduce the melting temperature of

A l_{2} O_{3}

.
Anode is made up of graphite,
So,

C (s) + 2 O^{2 -} ⟶ C O_{2} (g) + 4 e^{-}

Cathode is a steel vessel lined with graphite.

Q. Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite?

Hydrated $A l_{2} O_{3}$ precipitates, when $C O_{2}$ is bubbled through a solution of sodium aluminate.

Addition of $N a_{3} A l F_{6}$ lowers the melting point of alumina.

$C O_{2}$ is evolved at the anode during electrolysis.

The cathode is a steel vessel with a lining of carbon.

Q. Which among the following statement(s) is(are) true for the extraction of aluminium from bauxite?

Hydrated Al2​O3​ precipitates, when CO2​ is bubbled through a solution of sodium aluminate.

Addition of Na3​AlF6​ lowers the melting point of alumina.

CO2​ is evolved at the anode during electrolysis.

The cathode is a steel vessel with a lining of carbon.

Hydrated $A l_{2} O_{3}$ precipitates, when $C O_{2}$ is bubbled through a solution of sodium aluminate.

Addition of $N a_{3} A l F_{6}$ lowers the melting point of alumina.

$C O_{2}$ is evolved at the anode during electrolysis.