Spectrophotometric studies on the titanium(III) chromotropic acid complex

Abstract

The titanium(III)-chromotropic acid interaction was studied spectrophotometrically. The red complex showed maximum absorption at 440 mμ in aqueous medium at pH 7 and followed Lambert and Beer's Law in the concentration range of 0·666 × 10 −3−0·333 × 10 −4 M. Job's method, molar and slope ratio methods in aqueous solution at pH 7 exhibit a ratio of 1:1 (Ti 3+:ligand). The formation of the complex is very much affected by the pH of the solutions. Job's method at pH 1, 2·2, 4·4 and 5·5, yielded the ratios of 1:2, 1:1, 1:2 and 1:3 (Ti 3+:ligand). The log of formation constant and free energy of formation of the complex in aqueous medium at pH 7 were found to be 3·0 ± 0·3 and −4·0 ± 0·4 kcal/mole respectively at 25°C.