JEE Main · 2023 · 10 Apr 2023 · Shift 1 · d and f Block Elements

Prolonged heating is avoided during the preparation of ferrous ammonium sulphate to

(A)prevent oxidation✓ Correct
(B)prevent reduction
(C)prevent hydrolysis
(D)prevent breaking

Answer: (A)

Solution

Ferrous ammonium sulphate, Mohr's salt, is a double salt that holds iron in the +2 state. The iron(II) ion is readily oxidised to iron(III) by the oxygen of the air, and warming speeds this oxidation up. If the solution were heated for a long time during crystallisation, some iron(II) would turn to iron(III) and the product would be spoilt. Prolonged heating is therefore avoided to prevent the oxidation of iron(II).

JEE Main · 2023 · 10 Apr 2023 · Shift 1 · Single correct option

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