Balance the following redox reactions by ion – electron method:

(in acidic solution)

Following the steps as in part (A), we have the oxidation half reaction equation as:-


SO2(g) + 2H2O → SO42-(aq) + 4H+(aq) + 2e-


And the reduction half reaction as:-


Cr2O72-(aq) + 14H+(aq) + 6e-→ 2Cr3+(aq) + 7H2O


Multiplying the oxidation half reaction by 3 and then adding it to the reduction half reaction, we have the net balanced redox reaction equation as:-


Cr2O72-(aq) + 3 SO2(g) + 2H+(aq)→ 2Cr3+(aq) + 3SO42-(aq) + H2O


18