The chemical equation for the reaction of magnesium with iron(III) nitrate solution to form iron and solution is:

```

Mg(s) + 2Fe(NO3)3(aq) → Fe(s) + 2Mg(NO3)2(aq)

```

In this reaction, magnesium metal (Mg) reacts with iron(III) nitrate (Fe(NO3)3) solution to produce iron metal (Fe) and magnesium nitrate (Mg(NO3)2) solution. The reaction involves a single-replacement reaction, where magnesium displaces iron from the nitrate compound.