Experiment 13.2ab, the reaction between iron(III) ions and iodide ions,p368.

1.     Take 2 test-tubes 0.1M Fe³⁺ and 2 test-tubes 0.1M KI.

2.     Make 2 test-tube mixtures of about 2 cm 0.1M Fe³⁺ add 2cm3 0.1M KI.

       Changes occurring         .

3.     Add starch and Khexacyanoferrate(II) to each separate mixtures.

4.     Add Khexacyanoferrate to Fe²⁺ (should go blue).

Equation:2Fe³⁺_(aq)+2I^-_(aq)-->2Fe²⁺_(aq)+I_2(aq)

To measure electrode potentials of Fe3+-->Fe2+

1.     Use Cu cell as a reference and set things up as previous example w.r.t. Cu

2.     Use beaker filled with Fe³⁺/Fe²⁺ equilibrium and platinum electrode as a electrolyte (p.369)

3.     Measure E.m.f.=                       .

4.     Now use 2I^-_(aq)/I_2(aq) equilibrium instead of Fe³⁺/Fe²⁺ equilibrium. E.m.f.=              .

5.     Deduce the Pt|2I^-_(aq),I_2(aq) ¦ ¦ Fe³⁺,Fe²⁺ | Pt.

6.     Measure Pt|2I^-_(aq),I_2(aq) ¦ ¦ Fe³⁺,Fe²⁺ | Pt experimentally (need a 2nd Pt electrode)