ZnS-H2S-S-H2S-SO2-H2SO3-NaHSO2

1)ZnS + 2HCl = ZnCl2 + H2S 2)H2S=H2+S 3)S+H2=H2S 4)2H2S+3O2=2SO2+2H2O 5)SO2+H2O=H2SO3 6)NaOH + H2SO3 = NaHSO3 + H2O