POTENTIOMETRIC STUDIES OF OXIDES OF CHROMIUM

Chrome alum has been titrated with potassium chromate and chromic acid and \(pics\) versa using the cell : Pt-sol-K2^-SO₄ (satutated)^-NH₂SO₄-Hg₂SO₄-Hg. The nature of the E. M. F. and the ∆ E/∆ cc. curve has been found to be very complex. The peaks observed, which are reproducible, would indicate the formation of a large number of compounds of the general formula \(α\)CrO₃. \(b\)Cr₂O_s.

These curves would further indicate that the chromiurn ion in solution undergoes striking changes of electronic structure, with progressive oxidation.