8 KI-I + 9 H2SVIO4 8 KHSVIO4 + H2S-II + 4 I20 + 4 H2O

This is an oxidation-reduction (redox) reaction:

SVI + 8 e- S-II (reduction)

8 I-I - 8 e- 8 I0 (oxidation)

H2SO4 is an oxidizing agent, KI is a reducing agent.