6 KBr + 2 K2CrO4 + 8 H2SO4 → Cr2(SO4)3 + 5 K2SO4 + 8 H2O + 3 Br2
This is an acid-base reaction (neutralization): K2CrO4 is a base, H2SO4 is an acid.
This is an oxidation-reduction (redox) reaction:
6 Br-I - 6 e- → 6 Br0 (oxidation)
2 CrVI + 6 e- → 2 CrIII (reduction)
KBr is a reducing agent, K2CrO4 is an oxidizing agent.