5SO2 + 2KMnO4 + 2H2O -> 2MnSO4 + K2SO4 + 2H2SO4
K2Cr2O7 + H2S + H2SO4 -> Cr2(SO4)3 + K2SO4 + S + H2O ( đã tự CB)
K2Cr2O7 + 14HBr ->2CrBr3 + 2KBr + 3Br2 + 7H2O
K2Cr2O7 + 14HCl ->2CrCl3 + 2KCl +3 Cl2 + 7H2O
K2Cr2O7 + SO2 + 3H2SO4-> Cr2(SO4)3 + K2SO4 +3 H2O
Đây b ơi :>