3 Na2S2O5 + 6 CuSO4*5H2O + 10 NaOH → 2 Cu3(SO3)2*2H2O + 8 Na2SO4 + 31 H2O
This is an oxidation-reduction (redox) reaction:
6 CuII + 4 e- → 6 Cu4/3 (reduction)
2 SIV - 4 e- → 2 SVI (oxidation)
CuSO4*5H2O is an oxidizing agent, Na2S2O5 is a reducing agent.