The Activity Coefficients of Electrolytes with Particular Reference to Aqueous Mixtures of 2:2 with 1:1 Electrolytes

A. W. Gardner, E. Glueckauf
1971 Proceedings of the Royal Society A  
Muller's method for the exact solution of the Poisson-Boltzman equation (P.B.M.) has been used to produce tables for general application, for the potential, for the activity coefficients and for the osmotic coefficients of 2:2 electrolytes in aqueous solutions, both alone and in the presence of strong 1:1 electrolyte. The activity coefficients for 2:2 electrolytes were found to be equivalent to those derived by Bjerrum's method of ionic association up to values of s/a = z2e2jekTa of about 9.
more » ... ekTa of about 9. Beyond this value the Poisson-Boltzmann-Muller values of the activity coefficients are significantly higher (about 10% at sja = 11) and it is shown that the Bjerrum method is better in this range. The P.B.M. calculations show that in the presence of 1:1 electrolyte the Bjerrum treatment of ion association does not give a constant dissociation constant for a 2:2 electrolyte-even at infinite dilution of the latter-and this makes the Bjerrum method less useful when dealing with mixtures of 2:2 and 1:1 electrolytes. H CO lO PQ P h (M lO 0 5 h 2 I. i i I i i 5T CO© 05 CO lO 05 C l O 05 1> CO CO h h c o q oo c j q H h eo eo ei e* h I T I I I I I o o o o o o o rH rH rH rH rH rH rH X CO X CO X CO
doi:10.1098/rspa.1971.0047 fatcat:ta4bp2uivrcszmrqqjrq55touu