Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with $(i)$ iron $(II)$ ions,$(ii)$ $SO_2$,and $(iii)$ oxalic acid? Write the ionic equations for the reactions.

(N/A) Potassium permanganate is prepared from pyrolusite ore $(MnO_2)$. The ore is fused with $KOH$ in the presence of atmospheric oxygen or an oxidising agent like $KNO_3$ to form potassium manganate $(K_2MnO_4)$.
$2MnO_2 + 4KOH + O_2 \longrightarrow 2K_2MnO_4 + 2H_2O$
The green $K_2MnO_4$ is then oxidized to purple $KMnO_4$ either electrolytically or by passing $Cl_2$ or $O_3$ gas.
Electrolytic oxidation: $2MnO_4^{2-} + H_2O + [O] \longrightarrow 2MnO_4^- + 2OH^-$
$(i)$ Reaction with iron $(II)$ ions: $5Fe^{2+} + MnO_4^- + 8H^+ \longrightarrow 5Fe^{3+} + Mn^{2+} + 4H_2O$
$(ii)$ Reaction with $SO_2$: $5SO_2 + 2MnO_4^- + 2H_2O \longrightarrow 5SO_4^{2-} + 2Mn^{2+} + 4H^+$
$(iii)$ Reaction with oxalic acid: $5C_2H_2O_4 + 2MnO_4^- + 6H^+ \longrightarrow 10CO_2 + 2Mn^{2+} + 8H_2O$