THE CONDUCTOMETRIC ANALYSIS OF BINARY ELECTROLYTE-SOLUTIONS

A numerical method for computerized processing of conductometric measu rements is developed for binary electrolyte mixtures, which allows con centrations of individual components to be determined. The electrocond uctivity-dilution calibration curves for an arbitrary series of soluti ons with various initial ratios of the components are approximated by a polynomial of third to fourth degree with the subsequent approximati on by an analogous function of a matrix of coefficients. The net appro ximation of the calibration surface kappa(c(1), c(2)) thus obtained is used to identify component concentrations by comparing the experiment al and the modeling dilution curves with the aid of nonlinear regressi ve analysis. For a mixed electrolyte solution, the modeling concentrat ion curve kappa=f(c(1), c(2)) is then found, which coincides with the experimental curve at a certain combination (c(1)(0), c(2)(0)) with a minimum root-mean-square deviation in points of measurements. The meth od is shown to be applicable for electrolyte mixtures comprising indiv idual components with different transport characteristics, and the ext ent to which the characteristics differ defines the determination accu racy. A larger relative error in determining the concentration is intr insic to the component with a relatively low electroconductivity. The algorithm operation is illustrated with a nickel sulfate-sulfuric acid solution as an example.