KClO3 (aq) + 6 FeSO4 (aq) + 3 H2SO4 (aq) → KCl (aq) + 3 Fe2(SO4)3 (s) + 3 H2O (l)
This is an oxidation-reduction (redox) reaction:
ClV + 6 e- → Cl-I (reduction)
6 FeII - 6 e- → 6 FeIII (oxidation)
KClO3 is an oxidizing agent, FeSO4 is a reducing agent.
This is a precipitation reaction: Fe2(SO4)3 is the formed precipitate.