Predicting Specific Conductance from Electrolytic Properties and Ion Association in Some Aqueous Solutions

Specific conductances in aqueous solutions of electrolytes up to 0.1 N concentration were predicted with an extended form of the Onsager limiting equation and compared with measured values. For completely dissociated chloride solutions the calculations involved ionic conductance, electrophoretic and relaxation effects, and other electrolytic properties. Incompletely dissociated sulfate solutions required additional considerations of ion association of NaSO 4 ‐ , CaSO 4 °, and MgSO 4 °. Agreement was good between predicted and accepted literature conductance values. This quantitative description of conductance provides a theoretical explanation of why electrical conductivity underestimates analytically determined solute concentrations in waters and soil solutions containing moderate concentrations of SO 4 2‐ .