Activity coefficient of byions and ionic strength of polyelectrolyte solutions

With the polyelectrolyte solutions prepared by adding potassium chloride into the solution of sodium carboxymethyl celluloses in the various proportions, the activity of chloride ion was measured potentiometrically, from which the ionic strength of the sample solutions was computed. From these experimental results it has been found that Lewis' law of ionic strength, although it does not hold in the original sense as it is, seems applicable for the polyelectrolyte solutions if an assumption is permitted that the so‐called segment accompanied by a portion of counterions behaves like a permanent point‐charge ion. Thus, the degree of fixation of counterions was computed, and the dissociation state of strong polyelectrolyte was discussed. Furthermore, a brief report was made on the difference between the activity coefficients of byions and counterions in their thermodynamical meaning as well as on the connection of the nature of polyelectrolyte solutions with that of simple electrolyte solutions according to the authors' two phase conception.