Studies on the dissociation of rare-earth chromogenic reagent chlorophosphonazo-mK (CPAmK)

Abstract

The degree of dissociation of CPAmK has been studied by potentiometric and spectrophotometric methods. The dissociation constant of each step has been determined and thermodynamic constants <img src='http://www.niscair.res.in/jinfo/delta.gif' border=0><em>G</em>°, <img src='http://www.niscair.res.in/jinfo/delta.gif' border=0><em>H</em>°, <img src='http://www.niscair.res.in/jinfo/delta.gif' border=0><em>S</em>° of the dissociation process have been calculated. Quantum chemical calculations of the charge distributions at various atom in the molecule have also been made in support of the experimental observations.