$\mathrm{KMnO}_{4}$ oxidises $\mathrm{I}^{-}$ in acidic and neutral/faintly alkaline solution, respectively to

(A) $\mathrm{I}_{2}$ & $\mathrm{IO}_{3}^{-}$

(B) $\mathrm{IO}_{3}^{-}$ & $\mathrm{I}_{2}$

(C) $\mathrm{IO}_{3}^{-}$ & $\mathrm{IO}_{3}^{-}$

(D) $\mathrm{I}_{2}$ & $\mathrm{I}_{2}$

JEE Main · 2023 · 30 Jan 2023 · Shift 2 · d and f Block Elements

KMnO_{4}

oxidises

I^{-}

in acidic and neutral/faintly alkaline solution, respectively to

(A) $I_{2}$ & $IO_{3}^{-}$ ✓ Correct
(B) $IO_{3}^{-}$ & $I_{2}$
(C) $IO_{3}^{-}$ & $IO_{3}^{-}$
(D) $I_{2}$ & $I_{2}$

Answer: (A)

Solution

How far permanganate oxidises iodide depends on the acidity of the medium. In acidic solution the oxidation stops at the element, iodide being taken only as far as

I_{2}

. In neutral or faintly alkaline solution the oxidation is pushed further and the iodide is carried all the way to the iodate ion,

IO_{3}^{-}

. Thus iodide is oxidised to iodine in acid and to iodate in neutral or faintly alkaline medium.

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

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JEE Main · 2023 · 30 Jan 2023 · Shift 2 · d and f Block Elements

Solution

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