Speciation studies of mercaptosuccinic acid complexes of Pb(II), Cd(II), Hg(II) in dimethylformamide –water mixtures

Abstract

Equilibrium study on complex formation of Mercaptosuccinic acid with Pb(II),Cd(II) and Hg(II) has been investigated pH metrically in Dimethylformamide –water mixtures of 0.0 – 60.0% v/v at 303 K and maintaining 0.16 mol dm-3 ionic strength. The predominant species refined are MLH2 for Pb(II), MLH2 and ML2H for Cd(II) and ML2H and MLH for Hg(II). Models containing different number of species were refined by using the computer program MINIQUAD75. The best fit chemical models were arrived based on the statistical parameters. The trend in variation of complex stability constants with change in the dielectric constant of the medium is explained on the basis of electrostatic and non electrostatic forces.