Given below are two statements: Statement I: During Electrolytic refining, the pure metal is made to act as anode and its impure metallic form is used as cathode. Statement II: During the Hall-Heroult electrolysis process, purified \(\mathrm{Al}_{2} \mathrm{O}_{3}\) is mixed with \(\mathrm{Na}_{3} \mathrm{AlF}_{6}\) to lower the melting point of the mixture. In the light of the above statements, choose the most appropriate answer from the options given below:

(A) Statement I is incorrect but Statement II is correct

(B) Both Statement I and Statement II are incorrect

(C) Statement I is correct but Statement II is incorrect

(D) Both Statement I and Statement II are correct

JEE Main · 2023 · 30 Jan 2023 · Shift 2 · General Principles and Processes of Isolation of Metals

Given below are two statements:

Statement I: During Electrolytic refining, the pure metal is made to act as anode and its impure metallic form is used as cathode.
Statement II: During the Hall-Heroult electrolysis process, purified

Al_{2} O_{3}

is mixed with

Na_{3} AlF_{6}

to lower the melting point of the mixture.
In the light of the above statements, choose the most appropriate answer from the options given below:

(A)Statement I is incorrect but Statement II is correct✓ Correct
(B)Both Statement I and Statement II are incorrect
(C)Statement I is correct but Statement II is incorrect
(D)Both Statement I and Statement II are correct

Answer: (A)

Solution

The first statement has the electrodes the wrong way round. In electrolytic refining the impure metal is made the anode and dissolves, while pure metal deposits on the cathode; placing the pure metal at the anode, as written, is incorrect. The second statement is sound: in the Hall–Héroult process cryolite,

N a_{3} Al F_{6}

, is added to the purified alumina so that the mixture melts at a far lower temperature and conducts the current well. Hence the first statement is incorrect while the second is correct.

JEE Main · 2023 · 30 Jan 2023 · Shift 2 · Single correct option

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JEE Main · 2023 · 30 Jan 2023 · Shift 2 · General Principles and Processes of Isolation of Metals

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