Transference numbers for aqueous solutions of trichloroacetic acid (HTCA) at 25°C by the emf method

Abstract

Values of transference numbers for the anion TCA− were determined at different concentrations of the acid at 25 °C, by the emf method. In the cell used: glass ¦HTCA (m) ¦HTCA (mR)¦glass, mR was kept constant at 0.1001 mol kg−1, while m was varied from 0.006 to 0.1 mol kg−1 . The values of the potential of this cell, Et, were related to those of the cell without transference, Ewt, by means of empirical polynomial expressions, that of the second order leading to the best results for T_(HTCA). The dependence of this transport parameter on the concentration of the acid was analyzed using the Longsworth graphic extrapolation method. From the limiting value thus obtained, T°_ (HTCA) = 0.0958 ± 0.0022, the limiting equivalent conductivity value for the acid, 386.9±0.9 Ω−1 cm2 mol−1, was calculated.