Question

Write the balanced equation for the following redox reaction:

Hydrogen peroxide reacts with permanganate ions in acidic solution producing manganese(II) ions and oxygen gas.

Answer 1

In general:

H2O2 + MnO4-2 + H+ --> Mn+2 + O2(g)

This coms typically from the reaction:

KMnO4 + H2O2 + H2SO4 → MnSO4 + O2 + H2O + K2SO4

Split

MnO4- -> Mn+2

H2O2 --> O2

Balance H

MnO4- + 8 H+ → Mn2+ + 4 H2O

H2O2 --> O2 + 2H+

Balance charges

MnO4- + 8 H+ + 5 e- → Mn2+ + 4 H2O

H2O2 --> O2 + 2H+ +2e-

balance e-

2MnO4- + 16H+ + 10e- → 2Mn2+ + 8H2O

5H2O2 --> 5O2 + 10H+ + 10e-

add both

5H2O2 + 2MnO4- + 16H+ + 10e- → 2Mn2+ + 8H2O + 5O2 + 10H+ + 10e-

cancel terms

5H2O2 + 2MnO4- + 6H+ → 2Mn2+ + 8H2O + 5O2