Question
Which among the following statement(s) is (are) true for the extraction of aluminium from bauxite?
JEE Advanced
Chemistry
General Principles and Processes of Isolation of Metals
2020
JEE Advanced 2020 (Paper 2)
JEE Advanced Chemistry Question (2020) — Solution
Options
- 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.
Answer
D. The cathode is a steel vessel with a lining of carbon.
Step-by-step solution
(A) 2 NaAlO 2 + 3 H 2 O + CO 2 ⟶ 2 Al ( OH ) 3 + Na 2 CO 3 (B) In Hall-Heroult process Na 3 Al / F 6 and CaF 2 is mixed with Al 2 O 3 to lower melting point and increase conductivity. (C) Anode  C ( s ) + 2 O 2 − ( melt ) → CO 2 ( g ) + 4 e − (D) Steel cathode with carbon lining and graphite anode are used.
Related: Chemistry — General Principles and Processes of Isolation of Metals · All PYQ Banks