Cr^{VI} + 3 e^{-} → Cr^{III}

S^{IV} - 2 e^{-} → S^{VI}

1. | K + _{2}Cr_{2}O_{7}SO + _{2}H → Cr_{2}SO_{4}_{2}(SO_{4})_{3} + K_{2}SO_{4} + H_{2}O |

2. | K + _{2}Cr_{2}O_{7}SO + _{2}H → KCr(SO_{2}SO_{4}_{4})_{2} + H_{2}O |