Dvfusion / Electrolyte Solutions / Nonequilibrium Phenomena / Thermodynamics / Transport Properties The diffusion coefficients Dlt, DI2, D21, and Dz2 of the three systems MgC12(1) + KCl(2) + H20(3), CdC12(1) + KCl(2) + H20(3), and ZnC12(1) + KCl(2) + H20(3) have been measured at 25°C. The diaphragm cell method was applied. Diffusion coefficients for the following concentrations were obtained c1 = c2 = 0.25, 0.5, 0.75 M, and c, = 0.25, 0.5, 0.75 M, c2 = 2cl = 0.5, 1.0, 1.5 M. The D,J values which refer to the cell fixed system were transformed to the D; referring to the solvent fixed coordinate system. By the aid of thermodynamic data taken from the literature and from measurements with cells involving the solutions studied the derivatives of the partial chemical potentials apL,/acJ were determined. From all these data the phenomenological coefficients sl; were calculated and we found the result that for MgC12 + KCl + H 2 0 S2i2 = a;, is valid whereas for the complex forming systems CdClZ + KCl and ZnC1, + KCl our study yielded phenomenological coefficients SZ;, + all.
= .(4) This is supposed to be a general law being valid for all irreversible processes where linear flux equations withwhere t + and t-are the cationic and anionic transference numbers, respectively, E and AE are voltage and electromotive force, respectively, lI is the Peltier heat. According to Eq. (7) the streaming current is equal to the electroosmotic pressure, according to Eq. (8) the streaming potential is equal to the electroosmotic coefficient. Eq. (5) is derived from the fundamental equation of electrochemistry [6-81 *)with Ji given by Eq. (2). ti, is one of the transference numbers referring to component i, M i is the molecular mass of component i, j is the electric current density, divj = 0. The quan-*) In the following vector notation is omitted.