2 FeS2-I + 7 O20 + 2 H2O-II 2 FeSVIO4-II + 2 H2SVIO4-II

This is an oxidation-reduction (redox) reaction:

4 S-I - 28 e- 4 SVI (oxidation)

14 O0 + 28 e- 14 O-II (reduction)

Change the oxidation states