MnCl2 (aq) + 2 KOH (aq) + H2O2 (aq) → MnO2 (s) + 2 KCl (aq) + 2 H2O (l)
This is an oxidation-reduction (redox) reaction:
MnII - 2 e- → MnIV (oxidation)
2 O-I + 2 e- → 2 O-II (reduction)
MnCl2 is a reducing agent, H2O2 is an oxidizing agent.
This is a precipitation reaction: MnO2 is the formed precipitate.