The Mn³⁺ ion is unstable in solution and undergoes disproportionation to give Mn²⁺, MnO₂, and H⁺ ion. Write a balanced ionic equation for the reaction.

The given reaction can be represented as follows:

The oxidation half equation is:-

The oxidation number is balanced by adding one electron as:

The charge is balanced by adding 4H⁺ ions as:

The O atoms and H⁺ ions are balanced by adding 2H₂O molecules as:

The reduction half equation is:

The oxidation number is balanced by adding one electron as:

The balanced chemical equation can be obtained by adding oxidation and reduction half equations to get the desired equation as: -