Redox Reactions Question 3

\ce{5H2O2(aq) + 2MnO4-(aq) + 6H+(aq) -> 2Mn^{2+}(aq) + 8H2O(l) +5O2(g)}

In a titration experiment, $\ce{H2O2(aq)}$ reacts with aqueous $\ce{MnO4-(aq)}$ as represented by the equation above.

Which element is being oxidized during the titration, and what is the element's change in oxidation number?

Oxygen, which changes from -1 to 0

Oxygen, which changes from 0 to -2

Manganese, which changes from -1 to +2

Manganese, which changes from +7 to +2

Approach

Although oxygen typically has an oxidation state of -2 in compounds, it is -1 in hydrogen peroxide $\ce{H2O2}$ . The oxidation state for oxygen in diatomic oxygen is 0.

The oxidation state of manganese changes from +7 to +2, but this is reduction (gain of electrons).