2 CuII-I + 4 H2SVIO4 2 CuIISVIO4 + 2 SIVO2 + I20 + 4 H2O

This is an oxidation-reduction (redox) reaction:

2 CuI - 2 e- 2 CuII (oxidation)

2 SVI + 4 e- 2 SIV (reduction)

2 I-I - 2 e- 2 I0 (oxidation)

Change the oxidation states