JEE Main Chemistry question

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

Not in JEE Main or NEET syllabus

Electrolytic reduction of alumina to aluminium by Hall-Heroult process is carried out

(A)In the presence of NaCl
(B)In the presence of fluorite
(C)In the presence of cryolite which forms a melt with lower melting pointCorrect
(D)In the presence of cryolite which forms a melt with higher melting point

Answer: (C)

Solution

Pure alumina melts only above 2000°C, which is energy-prohibitive; dissolving it in molten cryolite (NaAlF) lowers the melting point of the mixture to about 950°C and also improves

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Question ID VK-145214