JEE Advanced2022ChemistryGeneral Principles and Processes of Isolation of MetalsActual
The electrochemical extraction of aluminium from bauxite ore involves
Options
- Athe reaction of Al 2 O 3 with coke C at a temperature > 2500 ° C .
- Bthe neutralization of aluminate solution by passing CO 2 gas to precipitate hydrated alumina Al 2 O 3 . 3 H 2
- Cthe dissolution of Al 2 O 3 in hot aqueous NaOH .
- Dthe electrolysis of Al 2 O 3 mixed with Na 3 AlF 6 to give Al and CO 2 .
Correct answer
B. the neutralization of aluminate solution by passing CO 2 gas to precipitate hydrated alumina Al 2 O 3 . 3 H 2
Step-by-step solution
(A) The reduction of Al 2 O 3 with coke C at a temperature > 2500   ° C is not carried out due to the formation of carbides. (B) It is correct as neutralisation of aluminate solution is done by passing CO 2 gas to precipitate hydrated alumina. (C) Reaction of powdered one is carried out with hot concentrated NaOH at 473   K - 523   K and 35 - 36 bar pressure. (D)Aluminium In the metallurgy of aluminium, purified Al 2 O 3 is mixed with Na 3 AlF 6 or CaF 2 which lowers the melting point of the