Diffusion and Reverse Diffusion of lons in Mixed Solutions of Strong Electrolytes

Abstract

It was known that the differential equation (eq.(1)), which deals with diffusion of each ion in mixed solutions of electrolytes, gave the results which agreed well with the observed phenomenological diffusion coefficients when it was solved numerically by trial and error method. In the present paper, the calculation is extended to find the relationship between diffusion coefficients of ions and thier properties, especially their charges and moblities. The results of the computation obtained were used to calculated values of R1/pq (eq.(2I)) which give the relative value of the apparent diffusion coefficients of i-ion in a certain solution to those in the standard electrolytes. In order to elucidate a tethephyca lmean in gs of the d ie ren tia lequa tion, the equatn was so Ved in terms of theapproximatin that the C0 ncentration sofio n distribute linearly m thed iu son layer. The calculation was mamly Carriedou tab out the solutions contain in gt WQ electrolytes with comm DnaniDn A SareSut, it bec ameevden t thatm the solution Conta in ingtwo electro lytes, the catonof largermob ility diu sesmore rapidly and that of smaller mob ilityd iu sesmore slow than that mtheso tioncontainings ing leelectrolyte (Fig 3, Fig.4), and that in mixed solution of and electro Iy tes, the di Vale nt Catin d ses Counter to concentration grad ient if the mob ilty of amon is relatively sm an (Fig.6, 9). Calcu1ated pgvalues a greed with ob served on es shownm tne llterature about the solutions of Sin gle electro Iy tes (Fig.1) and a lso With Qurexperimenta I Vauab Qut the mX eds. utiQns of two electrolytes KC MgCl, H, O and KHAsp-Mg(HAsp), -H, O, (Fig.2). The Haskell equation on the diffusion coefficient of an electrolyte was generalized by introducing correction factor which concerned with the concentration dependence on the activity coefficient (eq 20).