POLAROGRAPHIC BEHAVIOUR OF SOME ACID DYES

The polarographic behaviour of three acid dyes Crocein Orange G, Acid Alizarin Violet N and Acid Orange 10 in aqueous buffered solutions is represented. It is clear from the obtained results that the half wave potential shifts to more negative values as to be expected for processes that consume protons. The results indicate that the process of reduction is irreversible. The polarographic diagrams of the studied dyes gives one difined irreversible wave. The interpretation of the polarographic reduction wave was discussed. The diffusion coefficients of the three dyes were obtained. The aggregation constant in aqueous solution has been calculated in terms of a monomer-dimer equilibrium.