Question

Balance each of the following RedOx reactions occurring in acidic conditions:

Fe2+(aq) + MnO41-(aq) → Fe3+(aq) + Mn2+(aq)

Br2(l) + SO2(g) → Br1-(aq) + SO42-(aq)

Cu(s) + NO31-(aq) → Cu2+(aq) + NO2(g)

HgS(s) + Cl1-(aq) + NO31-(aq) → HgCl42-(aq) + NO2(g) + S(s)

Cl2(g) → ClO31-(aq) + Cl1-(aq)

Answer 1

Ans :

To balance the redox reactions , start by writing the oxidation and reduction half reactions seperately.

Then balance all other atoms except hydrogen and oxygen .

To balance the oxygen and hydrogen atoms , add water and protons respectively.

Balance the charges by adding electrons.

Add the two half reactions and simplify to get the balanced redox reactions as :

5Fe2+(aq) + MnO41-(aq) + 8H+ → 5Fe3+(aq) + Mn2+(aq) + 4H2O (l)

Br2(l) + SO2(g) +2H2O (l) → 2Br1-(aq) + SO42-(aq) + 4H+

Cu(s) + 2NO31-(aq) + 4H+ → Cu2+(aq) + 2NO2(g) + 2H2O (l)

HgS(s) + 4Cl1-(aq) + 2NO31-(aq) +4H+ → HgCl42-(aq) + 2NO2(g) + S(s) + 2H2O

3Cl2(g) + 3H2O (l) → ClO31-(aq) + 5Cl1-(aq) + 6H+