A solution of `KMnO_(4)` on reduction yields either a colourless solution or a brown precipitate or a green solution depending on pH of the solution. What different stages of the reduction do these represent and how are they carried out ?

Explanation

Oxidising behaviour of `KMnO_(4)` depends on pH of the solution.
In acidic medium `(pH lt 7)`
`MnO_(4)^(-) + 8H^(+) + 5e^(-) rarrunderset("Colourless")(Mn^(2+))+4H_(2)O`
In alkaline medium `(pH gt 7)`
`MnO_(4)^(-) + e^(-) rarrunderset(("Green"))(MnO_(4)^(2-)`
In neutral medium `(pH = 7)`
`MnO_(4)^(-)+2H_(2)O + 3e^(-)rarrunderset(("Brown ppt"))(MnO_(2)) + 4OH^(-)`