H2SO4 (aq) → H2 (g) + S (s) + 2 O2 (g)
This is an oxidation-reduction (redox) reaction:
SVI + 6 e- → S0 (reduction)
2 HI + 2 e- → 2 H0 (reduction)
4 O-II - 8 e- → 4 O0 (oxidation)
H2SO4 is an oxidizing agent, H2SO4 is an oxidizing agent, H2SO4 is a reducing agent.
This is a precipitation reaction: S is the formed precipitate.
This is a gas evolution reaction, H2 and O2 is the formed gas.