Oxidation-Reduction (Redox) Titrations:

The conductometric technique is not well suited to the study of oxidation-reduction titrations. Almost all such reactions must be carried out in the presence of a huge excess of acid or base that more or less fully masks the change in conductance because of the redox reaction. A classical instance is the titration of Fe (II) along with potassium permanganate in that, say, a 0.01 M solution of Fe (II) in 0.5 M sulphuric acid is titrated along with 0.02 M potassium permanganate. While the reaction

5 Fe²⁺   + MnO₄^- + 8 H+ = 5 Fe³⁺   + Mn²⁺ + 4 H₂O

does consume hydrogen ions, thus decreasing the conductance of the solution up to the equivalence  point, the fraction of hydrogen ion thus removed is associative small. The whole change in conductance is not appreciable and cannot be detected along with accuracy through the common equipment for the conductometric titrations.