2 MnCl2 (aq) + 5 Br2 (aq) + 16 NaOH (aq) → 2 NaMnO4 (aq) + 10 NaBr (aq) + 4 NaCl (aq) + 8 H2O (l)
This is an oxidation-reduction (redox) reaction:
10 Br0 + 10 e- → 10 Br-I (reduction)
2 MnII - 10 e- → 2 MnVII (oxidation)
Br2 is an oxidizing agent, MnCl2 is a reducing agent.