4 KMnO4 (aq) + 2 H2SO4 (aq) → 4 MnO2 (s) + 2 K2SO4 (aq) + 3 O2 (g) + 2 H2O (l)
This is an oxidation-reduction (redox) reaction:
4 MnVII + 12 e- → 4 MnIV (reduction)
6 O-II - 12 e- → 6 O0 (oxidation)
This is a precipitation reaction: MnO2 is the formed precipitate.
This is a gas evolution reaction, O2 is the formed gas.