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When XO2 is fused with an alkali metal hydroxide in presence of an oxidizing agent such as KNO3, a dark green product is formed which disproportionate in acidic solution to afford a dark purple solution, X is - [JEE-Main On line-2018]

1. Mn
2. Cr
3. V
4. Ti

Correct answer: Mn

Solution

Fusing MnO2 with KOH and an oxidizer (KNO3) gives green potassium manganate K2MnO4 (Mn +6), which disproportionates in acid to purple permanganate KMnO4. So X = Mn.

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