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Identify the statement that is NOT correct: (A) MnO2 dissolves in concentrated HCl but does not give Mn(IV) ions in solution (B) MnO2 reacts with hot concentrated H2SO4, evolving oxygen gas (C) K2MnO4 is produced when MnO2 fused with KOH is oxidised by air, KNO3, PbO2 or NaBiO3 (D) The decomposition of acidified KMnO4 is not promoted by sunlight

1. MnO2 dissolves in conc. HCl, but does not form Mn4+ ions
2. MnO2 react with hot concentrated H2SO4 liberating oxygen
3. K2MnO4 is formed when MnO2 in fused KOH is oxidised by air, KNO3, PbO2 or NaBiO3
4. Decomposition of acidic KMnO4 is not catalysed by sunlight.

Correct answer: Decomposition of acidic KMnO4 is not catalysed by sunlight.

Solution

The decomposition of acidic KMnO4 IS catalysed (accelerated) by sunlight, so statement (D) is the incorrect one. Statements A, B and C are correct properties of MnO2 chemistry.

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