JEE Main · 2022 · 28 Jul 2022 · Shift 1 · General Principles and Processes of Isolation of Metals

Which of the reaction is suitable for concentrating ore by leaching process?

(A) $2 Cu_{2} S + 3 O_{2} \to 2 Cu_{2} O + 2 SO_{2}$
(B) $Fe_{3} O_{4} + CO \to 3 FeO + CO_{2}$
(C) $Al_{2} O_{3} + 2 NaOH + 3 H_{2} O \to 2 Na [Al (OH)_{4}]$ ✓ Correct
(D) $Al_{2} O_{3} + 6 Mg \to 6 MgO + 4 Al$

Answer: (C)

Solution

Leaching is a process where the ore is treated with a suitable reagent to dissolve it selectively, leaving impurities behind. Option (C) shows the reaction of alumina (

Al_{2} O_{3}

) with NaOH to form soluble sodium aluminate (

Na [Al (OH)_{4}]

), which is the Bayer process for concentrating bauxite ore. The other reactions represent roasting (A), reduction (B), and thermite process (D), not leaching.

JEE Main · 2022 · 28 Jul 2022 · Shift 1 · Single correct option

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JEE Main · 2022 · 28 Jul 2022 · Shift 1 · General Principles and Processes of Isolation of Metals

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