Polarographic Study of Complexes of Cadmium(II) and Lead(II) with Ethoxyacetate Ions

Department of Chemistry, Punjab University, Chandigarh-160 014

Reduction of the complexes of cadmium(II) and lead(II) at d.m.e. in aqueous and aqueous-methanol media at μ=1.0 M (NaCIO₄) at 15±0.1 and 25±0.1° is reversible and diffusion-controlled. Four complex species are formed in either case. The overall stability constants of 1 : 1, 1 : 2, 1 : 3 and 1 : 4 complexes have been determined by DeFord and Hume, and Mihailov's mathematical treatment. Lead(II) complexes have been found to be much stronger than the corresponding cadmium(II) complexes. Thermodynamic parameters have been determined. Percentage distribution of cadmium(II) and feud(Il) present in various forms in equilibrium as a function of the ligand concentration have been calculated.