A Spectrophotometric Study on the Thorium Complex of o-Hydroxyphenyl-azo-chromotropic Acid

Abstract
o-Hydroxyphenyl-azo-chromotropic acid was used as a colorimetrie reagent for thorium. The acid dissociation constants of the reagent have been determined by the pH titration method. The pK1 (for the dissociation of the phenolic hydroxyl group) and pK2 (for that of the naphtholic hydroxyl group) were found to be 7.60 and 10.60 respectively at 25°C and μ=0.1. The reagent forms a violet 1 : 1 complex in an acidic solution, and its apparent stability constant is measured spectrophotometrically.

This publication has 1 reference indexed in Scilit: