Question

The following skeletal oxidation-reduction reaction occurs under acidic conditions. Write the balanced REDUCTION half reaction.
Fe + SO42- Fe2+ + SO2

Answer 1

Answer:

An example is given below of the reaction of iron(III) sulfate with magnesium.

Unbalanced reaction: Mg(s) + Fe2(SO4)3(aq) → Fe(s) + MgSO4(aq)

This reaction is split into two half-reactions, one that involves oxidation and one that involves reduction.

Reduction: Fe3+(aq) + 3e– → Fe(s)

Oxidation: Mg(s) → Mg2+(aq) + 2e–

This pair of half-reactions can be balanced by ensuring that both have the same number of electrons. To do this, multiply the oxidation half-reaction by 3 and the reduction half-reaction by 2, so that each half-reaction has 6e–.

2 Fe3+(aq) + 6e– → 2 Fe(s)

3 Mg(s) → 3 Mg2+(aq) + 6e–

Adding these two half reactions together gives the balanced equation:

2 Fe3+(aq) + 3 Mg(s) → 2 Fe(s) + 3 Mg2+(aq)

Notice that the sulfate ion (SO42-) is ignored. This is because it does not take part in the reaction; it is a spectator ion.