Mean distance of Closest approach of ions in NaCl(aq.) at 25 deg C calculated from degrees of association using Bjerrum's theory

摘要

This paper demonstrates, for the first time, the applicability to 1:1 strong electrolytes of Bjerrum's pioneering theory, which relates the degree of ionic association with the mean distance a of closest approach of ions. It can be noted that only recently, strong electrolytes like NaCl were shown to be incompletely dissociated in aqueous solutions. The present data on the degrees of dissociation of NaCl (aq.) at 25 deg C have been used to calculate the values of a for concentrations from zero to saturation, using Bjerrum's theory. It is found that both Q(b), the Bjerrum's integral, and a are simple functions of the molal volume and concentration and that at saturation, a is less than q, the critical distance.