Polarographic Study of La (III)-3-Hydroxy-3-P-Chlorophenyl-1-PSulphonato (Sodium Salt) Phenyltriazene Complex

The electrochemical behavior of complex of La (III) with 3-hydroxy-3-p-chlorophenyl-1-p-sulphonato (sodium salt) phenyltriazene (HCST) was studied. It was observed that HCST forms 1:1 complex with La (III) in Citric acid and Na₂HPO₄ buffer solution between pH 6.0 to 7.5. It was found that the reduction process of La (III) - HCST complex is three electron reversible reduction process. The stability constant of the 3-hydroxy-3-p-chlorophenyl-1-p-sulphonato (sodium salt) phenyltriazene complex was evaluated with the Lingane method at different ligand concentrations. The logarithm value of stability constant of 1:1 La (III) - HCST complex is 18.78.