2e- + 2 H2O +2mn3+-------------=mn2+ mnO2 +4H+
is the reaction is correct?

The disproportionation of the Mn3+ ion in solution can be represented by the following balanced ionic equation:

2Mn3+ (aq) → Mn2+ (aq) + MnO2 (s) + 2H+ (aq)

Explanation:
1. Oxidation State of Mn:
The Mn3+ ion has a +3 oxidation state, which means it has lost three electrons.

2. Disproportionation:
Disproportionation is a redox reaction in which the same element undergoes both oxidation and reduction simultaneously. In this case, the Mn3+ ion undergoes disproportionation to form both Mn2+ and MnO2.

3. Formation of Mn2+:
In the reaction, two Mn3+ ions each lose one electron to form two Mn2+ ions. This is a reduction process as the Mn3+ ions are gaining electrons and their oxidation state decreases from +3 to +2.

4. Formation of MnO2:
Simultaneously, one Mn3+ ion loses two electrons to form MnO2, which is manganese dioxide. This is an oxidation process as the Mn3+ ion is losing electrons and its oxidation state increases from +3 to +4.

5. Formation of H+:
The reaction also involves the formation of two H+ ions. This indicates that the reaction is taking place in an acidic solution.

6. Balanced Equation:
By balancing the number of atoms and charges on both sides of the equation, the balanced ionic equation for the disproportionation of the Mn3+ ion is obtained as:

2Mn3+ (aq) → Mn2+ (aq) + MnO2 (s) + 2H+ (aq)

In this equation, the charges are balanced, and the number of atoms of each element is the same on both sides.

Overall, the disproportionation of the Mn3+ ion in solution results in the formation of Mn2+, MnO2, and H+ ions. This reaction occurs due to the unstable nature of the Mn3+ ion, which undergoes simultaneous oxidation and reduction processes to achieve more stable oxidation states.