CONDUCTANCES AND SURFACE TENSIONS OF AQUEOUS SOLUTIONS OF SODIUM DECANOATE, SODIUM LAURATE, AND SODIUM MYRISTATE, AT 25° AND 35°

Abstract

The equivalent conductances of aqueous solutions of sodium decanoate, sodium laurate, and sodium myristate have been determined from the very dilute region up to saturation concentration, at 25° and 35°. The limiting conductances have been obtained from the measurements in the usual way. In addition and for the sake of completeness, the limiting equivalent conductances of sodium formate, sodium acetate, sodium propionate, and sodium butyrate have also been determined at 35°, since they were not known at this temperature.The effect of increasing chain length on mobility is discussed. From a consideration of the experimental and the theoretical values of the slopes of the plots of equivalent conductance against the square root of the concentration, it is concluded that some sort of interaction, possibly a reversible dimerization of anions, occurs, even in the dilute region, and this could account for the lower experimental values of the slope. This phenomenon has been observed with other long chain electrolytes, however, and the hypothesis of dimerization is not the only possible one.The critical micelle concentrations have been determined, and recent concepts of micelle formation are applied to interpret their structure. The surface tensions of the aqueous solutions have been measured at 25° and 50°.