Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with (i) iron(II) ions (ii) SO2 and (iii) oxalic acid? Write the ionic equations for the reactions.

Potassium permanganate is manufactured on a large scale due to its manifold uses in the laboratory. In the first stage, pyrolusite, which is the mineral form of manganese dioxide, is fused with potassium hydroxide and heated in air or with potassium nitrate (a source of oxygen). This leads to the formation of potassium manganate, which on electrolytic oxidation in alkaline solution gives potassium permanganate.

MnO2 + 2OH− + O2 → MnO42− + H2O
MnO42− + Cl2 → MnO4− + 2Cl−

(1)with iron
MnO4^- + Fe2+ + 8H+ -------Mn+2 + 5Fe^3+ +4h20
(2)2Mno4- +10SO2 +5O2 +4H20 ------2mn+2 +10SO4^2- +8H+
(3) 2MnO4- +5C2O4^2- +16H+ -------2Mn+2 +10CO2 +8H20