1. Identify the Half-Reactions
* Oxidation: H₂O₂ → O₂
* Reduction: MnO₄⁻ → Mn²⁺
2. Balance Atoms (Except for O and H)
* Both half-reactions are already balanced in terms of Mn and O.
3. Balance Oxygen Atoms
* Oxidation: H₂O₂ → O₂ + 2H₂O
* Reduction: MnO₄⁻ → Mn²⁺ + 4H₂O
4. Balance Hydrogen Atoms
* Oxidation: H₂O₂ → O₂ + 2H₂O
* Reduction: MnO₄⁻ + 8H⁺ → Mn²⁺ + 4H₂O
5. Balance Charge
* Oxidation: H₂O₂ → O₂ + 2H⁺ + 2e⁻
* Reduction: MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O
6. Equalize Electron Transfer
* Multiply the oxidation half-reaction by 5 and the reduction half-reaction by 2:
* 5H₂O₂ → 5O₂ + 10H⁺ + 10e⁻
* 2MnO₄⁻ + 16H⁺ + 10e⁻ → 2Mn²⁺ + 8H₂O
7. Combine the Half-Reactions
2MnO₄⁻ + 5H₂O₂ + 6H⁺ → 2Mn²⁺ + 5O₂ + 8H₂O
Final Balanced Redox Reaction:
2MnO₄⁻(aq) + 5H₂O₂(aq) + 6H⁺(aq) → 2Mn²⁺(aq) + 5O₂(g) + 8H₂O(l)
