pH-Metric Studies on the Metal (Vanadyl and Thorium) Pyrophosphate Reaction

Chemical Laboratories, University of Roorkee, Roorkee, (U.P.). Manuscript received 27 November 1975, revised 14 October 1976, accepted 22 February 1977 The interaction or VO2+ and Th4+ ions with pyrophosphoric acid has been studied by potentiometric technique. pH-titrations or reaction mixtures containing metal salt and pyrophosphoric acid have provided evidence for the formation of metal ligand chelate containing metal ion and pyrophosphoric acid in the molar ratio of 1 : 2 and 2 : 1. From the analysis of pH-metric data, various reaction steps including polymerisation of 1 : 2 (metal : pyrophosphate) in the high pH-range have been suggested. The values of the stability constant β, for VO2+ and Th4+ complexes were found to be 0.370 x 102 and 0.400 x 102 respectively