Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Aluminium is extracted from bauxite by the electrolysis of molten mixture of $\mathrm{Al}_{2} \mathrm{O}_{3}$ with cryolite. Reason (R): The oxidation state of Al in cryolite is +3 . In the light of the above statements, choose the most appropriate answer from the options given below :

(A) Both (A) and (R) are correct but (R) is not the correct explanation of (A)

(B) Both (A) and (R) are correct and (R) is the correct explanation of (A)

(C) (A) is true but (R) is false

(D) (A) is false but (R) is true.

JEE Main · 2021 · 31 Aug 2021 · Shift 1 · General Principles and Processes of Isolation of Metals

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Aluminium is extracted from bauxite by the electrolysis of molten mixture of

Al_{2} O_{3}

with cryolite.
Reason (R): The oxidation state of Al in cryolite is +3 .
In the light of the above statements, choose the most appropriate answer from the options given below :

(A)Both (A) and (R) are correct but (R) is not the correct explanation of (A)✓ Correct
(B)Both (A) and (R) are correct and (R) is the correct explanation of (A)
(C)(A) is true but (R) is false
(D)(A) is false but (R) is true.

Answer: (A)

Solution

Aluminium is obtained by electrolysing purified alumina dissolved in molten cryolite in the Hall-Heroult process, so the assertion is true. In cryolite,

N a_{3} Al F_{6}

, aluminium is indeed in the

+ 3

state, so the reason is also true. However, cryolite is added to lower the fusion temperature and raise the conductivity of the melt, not because of the oxidation state of aluminium in it. Both statements are true but the reason is not the correct explanation of the assertion.

JEE Main · 2021 · 31 Aug 2021 · Shift 1 · Single correct option

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JEE Main · 2021 · 31 Aug 2021 · Shift 1 · General Principles and Processes of Isolation of Metals

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