Zn+S=ZnS ZnS+2HCl=ZnCl2 + H2S 2H2S+O2=2H2O+2S S+O2=SO2 S(0) - 4e= S(+4) O2 +4e= 2O(-2) 2SO2+O2=2SO3 SO3 +H2O=H2SO4 H2SO4 + BaCl2=BaSO4+2HCl