S -> ZnS -> H2S -> SO2 -> H2SO3 -> Na2SO3
S + Zn = ZnS
ZnS +2HCl = ZnCl2 + H2S
2H2S +3O2 = 2SO2 + 2H2O
SO2 + H2O = H2SO3
H2SO3 + 2Na = Na2SO3 + H2
S -> ZnS -> H2S -> SO2 -> H2SO3 -> Na2SO3
S + Zn = ZnS
ZnS +2HCl = ZnCl2 + H2S
2H2S +3O2 = 2SO2 + 2H2O
SO2 + H2O = H2SO3
H2SO3 + 2Na = Na2SO3 + H2