Question #5e3e7

1 Answer
Mar 30, 2014

The iron-containing compound is iron(II) sulfate, FeSO₄.

The two possibilities are FeSO₄ and Fe₂(SO₄)₃.

We can decide by using a table of standard reduction potentials.

Cu²⁺(aq) + 2e⁻ → Cu(s); E° = +0.34 V
Fe(s) → Fe²⁺(aq) + 2e⁻; E° = +0.41 V
Cu²⁺(aq) + Fe(s) → Cu(s) + Fe²⁺(aq); E° = +0.75 V

Cu²⁺(aq) + 2e⁻ → Cu(s); E° = +0.34 V
Fe(s) → Fe³⁺(aq) + 3e⁻; E° = +0.04 V
3Cu²⁺(aq) + 2Fe(s) → 3Cu(s) + 3Fe²⁺(aq); E° = +0.38 V

The oxidation of Fe to Fe²⁺ has a higher value of E°. Thus the product is iron(II) sulfate, FeSO₄.