What is meant by 'disproportionation' of an oxidation state ? Give an example.

Explanation

When a particular oxidation state becomes less stable relative to other oxidation states, one lower, one higher, it is said to undergo disproportionation. For example, manganese (VI) becomes unstable relative to manganese(VII) and manganese (IV) in acidic solution.
`3Mn^("VI")O_(4)^(2-)+4H^(+)rarr2Mn^("VII")O_(4)^(-)+Mn^("IV")O_(2)+2H_(2)O`