THE INFLUENCE OF SIMPLE ELECTROLYTE ON THE BEHAVIOR OF SOME ACID DYESIN AQUEOUS-MEDIA

The influence of adding counter-ion such as Na+ on the dimerization of the two sulphonated az, dyes, C.I. Acid Red 14 and C.I. Acid Red 17 i n aqueous media has been studied spectrophotometrically. The observed hypochromic effect on increasing the amount of salt has been described . The dye concentration range where the dimerization equilibrium is ap plicable was chosen. No metachromatic behaviour was observed on changi ng the dye concentration and the amount of salt. This behaviour was at tributed to the ability of the counter-ion to disrupt the structure of water as well as reducing the electrostatic repulsion forces between dye anions which will lead to the increase of aggregation tendency of the dye species.