3 H2O2 (aq) + K2Cr2O7 (aq) + H2SO4 (aq) → Cr2O3 (s) + K2SO4 (aq) + 3 O2 (g) + 4 H2O (l)
This is an oxidation-reduction (redox) reaction:
6 O-I - 6 e- → 6 O0 (oxidation)
2 CrVI + 6 e- → 2 CrIII (reduction)
H2O2 is a reducing agent, K2Cr2O7 is an oxidizing agent.
This is a precipitation reaction: Cr2O3 is the formed precipitate.
This is a gas evolution reaction, O2 is the formed gas.