Sb2IIIO3 + 2 Br20 + 10 KOH 2 K3SbVO4 + 4 KBr-I + 5 H2O

This is an oxidation-reduction (redox) reaction:

4 Br0 + 4 e- 4 Br-I (reduction)

2 SbIII - 4 e- 2 SbV (oxidation)

Change the oxidation states