Study of Oxidation-Reduction Systems. III. The Reversible System Ti+4-Ti+3

Oxidation-reduction potentials of solutions of Ti+4 and Ti+3 have been determined as a function of time and dilution. It follows from this study that the equation of Nernst can be applied and that deviations which occur for more dilute solutions are due to the influence of the cathodic reduction current of the solvent, as is shown from the polarization curves. As the anodic oxidation of the reductant (Ti+3) occurs at more negative potentials than the cathodic reduction of the solvent, oxidation of Ti+3 cannot be avoided even in a nitrogen atmosphere. In solution all Ti+3 is eventually oxidized to Ti+4.