S-H2S-SO3-H2SO4-CuSO4-Cu(OH)2
S+H2-->H2S 2H2S+3O2-->2H2O+2SO2 , 2SO2+O2-->2SO3 SO3+H2O-->H2SO4 H2SO4+CuCL2-->CuSO4+2HCL CuSO4+2NaOH-->Cu(OH)2+Na2SO4