How will you obtain pure potassium permanganate `(KMnO4_)` crystals from its ore, pyrosulfite ? Give the steps involved and the reactions.

Explanation

`KMnO_(4)` is prepared by fusing pyrolusite ore with alkali in presence of air or any oxidising agent `(KNO_(3))` Conversion of pyrolusite `(MnO_(2))` to potassium manganate :
`2MnO_(2)+4KOH+O_(2) overset(Delta)to2K_(2)Mn_(2)O`
`2MnO_(2)+2K_(2)CO_(3)+O_(2) overset(Delta)to2K_(2)MnO_(4)+2CO_(2)`
Oxidation of potassium manganate to potassium permanganate
`3K_(2)MnO_(4)+2CO_(2) to 2KMnO_(4)+MnO_(2) +2K_(2)CO_(3)`
Or
`2K_(2)MnO_(4)+Cl_(2) to 2KMnO_(4)+2KCI`