JEE MainChemistryd and f Block Elements
In the industrial preparation of potassium permanganate from pyrolusite ore, the first step involves fusion with KOH and KNO ₃ to yield an intermediate coloured oxoanion 'P'. The second step involves the electrolytic oxidation of 'P' to yield the final oxoanion 'Q'. Which of the following statements correctly describes the magnetic nature of the oxoanions 'P' and 'Q'?
Options
- ABoth P and Q are diamagnetic.
- BP is diamagnetic and Q is paramagnetic.
- CP is paramagnetic and Q is diamagnetic.
- DBoth P and Q are paramagnetic.
Correct answer
C. P is paramagnetic and Q is diamagnetic.
Step-by-step solution
The fusion of pyrolusite ( MnO ₂ ) with KOH and KNO ₃ produces the green manganate ion, MnO ₄²⁻ , which is the intermediate oxoanion 'P'. In MnO ₄²⁻ , manganese is in the +6 oxidation state. The electronic configuration of Mn ⁶⁺ is [ Ar ] 3 d ^1 . Since it has one unpaired electron, 'P' is paramagnetic. Electrolytic oxidation of the manganate ion yields the purple permanganate ion, MnO ₄⁻ , which is the final oxoanion 'Q'. In MnO ₄⁻ , manganese is in the +7 oxidation state. The electronic configuration of Mn ⁷⁺ is