Br2+Na2SO3+H2O=2NaBr+H2SO4Br2+NaHSO3+H2O=NaBr+H2SO4
Br2+Na2SO3+H2O=2NaBr+H2SO42Br2+2NaHSO3+2H2O=Na2SO4+H2SO4+4HBr