8.21. 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 unbalanced chemical reaction is: Mn3+ (aq) → Mn2+ (aq) + MnO2? (s) + H+ (aq) The oxidation half reaction is, Mn3+ (aq) → MnO2? (s). To balance oxidation number, one electron is added on R.H.S. Mn3+ (aq) → MnO2? (s) + e− 4 protons are added to balance the charge. Mn3+ (aq) → MnO2? (s) + 4H+ (aq) + e− 2 water molecules are added to balance O atoms. The reduction half reaction is Mn3+ (aq) → Mn2+ (aq). An electron is added to balance oxidation number. Mn3+ (aq) + e− → Mn2+ (aq) Two half-cell reactions are added to obtain balanced chemical equation. 2Mn3+ (aq) + 2H2? O (l) → Mn2+ (aq) + MnO2? (s) + 4H+ (aq)

8.21. 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.

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Vishal Baghel | Contributor-Level 10

9 months ago

The unbalanced chemical reaction is:
Mn³⁺ (aq) → Mn²⁺ (aq) + MnO₂? (s) + H⁺ (aq)
The oxidation half reaction is,
Mn³⁺ (aq) → MnO₂? (s).
To balance oxidation number, one electron is added on R.H.S.
Mn³⁺ (aq) → MnO₂? (s) + e⁻
4 protons are added to balance the charge.
Mn³⁺ (aq) → MnO₂? (s) + 4H⁺ (aq) + e⁻
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