Given below are two statements :
Statement I : Potassium permanganate on heating at 573K 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 :

Solution

Chemistry ma’am · 3 steps

Both ions are tetrahedral, but count the d electrons: Mn(+7) has none, so permanganate is not paramagnetic.

1. Heating permanganate. Solid KMnO₄ decomposes on strong heating (around 513 K and above) to potassium manganate, manganese dioxide and oxygen. So at 573 K it does form K₂MnO₄, and Statement I is true.

   2KMnO₄ →(Δ) K₂MnO₄ + MnO₂ + O₂

   Ion	Oxidation state of Mn	d electrons	Shape	Magnetic nature
   MnO₄⁻ (permanganate)	+7	3d⁰, no unpaired	tetrahedral	diamagnetic
   MnO₄²⁻ (manganate)	+6	3d¹, one unpaired	tetrahedral	paramagnetic

2. Check Statement II. Both ions are tetrahedral, so that half is fine. But permanganate has no unpaired electron, so it is diamagnetic. The claim that both are paramagnetic fails, and Statement II is false.
3. So. Statement I is true and Statement II is false, which is option (a).

The idea to keep. For any oxo-anion, find the metal's oxidation state, then its d electron count. Zero unpaired electrons means diamagnetic, however dark the colour.

Answer from the NTA final answer key. Solution by PrepWiser.