Writing the oxidation numbers of all the atoms.
The Ox. no. of Cr has decreased while that of chlorine has increased.
Decrease in Ox. no. of Cr=6 units per molecule K2Cr2O7
Increase in Ox. no. of Cl=1 unit per molecule HCl
Eq. (ii) is multiplied by 6.
To balance chlorine and potassium, 14 molecules of HCl are required.
To balance hydrogen and oxygen, 7H2O are added to tướng RHS.
Hence, the balanced equation is,