Describe the preparation of potassium permanganate from pyrolusite ore. Write balanced chemical equation for one reaction to show oxidizing nature of potassium permanganate.

Explanation

Formation of `KMnO_4` : It is prepared by fusing pyrolusite ore `(MnO_2)` with caustic potash (KOH) or potassium carbonate in the presence of air to give a green mass due to the formation of potassium manganate.
`2MnO_2 = 4KOH + O_(2) overset("heat")(rarr) underset("(green mass)")underset("Magnanate")underset("Potassium")(2K_2MnO_4)+2H_2O`
`2MnO_2 + 2K_2CO_3 + O_3 rarr underset("Maganate")underset("Potassium")(2K_2MnO_4) + 2CO_2`
The solution is then treated with a current of chlorine or ozone to oxidise potassium manganate to potassium permanganate.
The solution is concentrated and the dark purple crystals of potassium permanganate separate out.
`2K_2MnO_4 + Cl_2 to 2KCI + 2KMnO_4`
`2K_2MnO_4 + O_3 +H_2O rarr 2KMnO_4 + 2KOH +O_2`
Oxidizing action of acidified `KMnO_4` on iron (II) ions .
`2KMnO_4 + 3H_2SO_4 to K_2SO_4 + 2MnO_4 + 3H_2O + 5[O]`
`([2FeSO_4 + H_2SO_4 + [O] to Fe_(2)(SO_4)_(3) + H_2O] xx 5)/(2KMnO_4 + 8H__2SO_4 + 10FeSO_4 rarr K_2SO_4 + 2MnO_4 + 5Fe_2(SO_4)_(3) + 8H_2O)`