The action of metals plant auxins has been a controversial subject of metal complexes, which have the wide spectrum of applications beginning with analytical chemistry and ending with medicinal chemistry. Chauhan, and Co-workers [1-11] have studied the affinity of metals to plant Auxins (IPA) highlighting their solution chemistry, synthesis, decomposition mechanism and kinetics. In the light of controversy still hanging on the subject mode of action of plant auxins it has been felt to pursue and continue studies on metal-plant auxin interaction in solution and solid state. The study of thermodynamic and stability constant etc. to be carried out potentiometrically applying the concept of Henderson Hasselback for Proton-ligand stability constant of plant auxin (IPA) and Bjerrum for the stability constants of metal-ligand systems. This paper reports on an extension of these studies on the interaction of the metal Ce (III) and Pr (III) with plant Auxins (IPA) in solution.

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Keywords: Auxin, Biologists, Interaction, Thermodynamic, Kinetic, Compositional.