JEE Main Chemistry question

Chemistry General Principles and Processes of Isolation of Elements (Metallurgy)JEE Main

Not in JEE Main or NEET syllabus

For the electrolytic refining of aluminium, the three fused layers consist of .

(A)Bottom: Cathode of pure Al; Middle: Cryolite and fluorspar; Upper: Anode of Al and Cu alloy
(B)Bottom: Cathode of Al and Cu alloy; Middle: Bauxite and cryolite; Upper: Anode of pure Al
(C)Bottom: Anode of impure Al; Middle: Cryolite and barium fluoride; Upper: Cathode of pure AlCorrect
(D)Bottom: Anode of Al and Cu alloy; Middle: Bauxite, cryolite and fluorspar; Upper: Cathode of pure Al

Answer: (C)

Solution

In the Hoopes electrolytic refining cell for aluminium, three immiscible molten layers stratify by density: the densest, impure Al-Cu alloy forms the bottom layer and acts as the anode; a molten mixture of cryolite and barium fluoride (the electrolyte) forms

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Question ID VK-145343