JEE Main · 2021 · 17 Mar 2021 · Shift 1 · d and f Block Elements

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Given below are two statements:
Statements I :Potassium permanganate on heating at 573 K forms potassium manganate.
Statement II: Both potassium permanganate and potassium manganate are tetrahedral and paramagnetic in nature.
In the light of the above statements, choose the most appropriate answer from the options given below:

(A)Statement I is true but statement II is false✓ Correct
(B)Both statement I and statement II are true
(C)Both statement I and statement II are false
(D)Statement I is false but statement II is true

Answer: (A)

Solution

On heating, potassium permanganate decomposes to potassium manganate, manganese dioxide and oxygen:

2KMn O_{4} \to K_{2} Mn O_{4} + Mn O_{2} + O_{2}

so the first statement holds. Both

Mn O_{4}^{-}

and

Mn O_{4}^{2 -}

are indeed tetrahedral, but manganese is

+ 7

in permanganate with a

3 d^{0}

core and no unpaired electron, which makes permanganate diamagnetic, while in manganate manganese is

+ 6

with

3 d^{1}

and is paramagnetic. The claim that both are paramagnetic therefore fails: Statement I is true but Statement II is false.

JEE Main · 2021 · 17 Mar 2021 · Shift 1 · Single correct option

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JEE Main · 2021 · 17 Mar 2021 · Shift 1 · d and f Block Elements

Solution

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