VOLUMETRIC PROPERTIES OF AQUEOUS-ELECTROLYTES AT HIGH-TEMPERATURE .2.B(OH)(3) AND B(OH)(3)-NAB(OH)(4)-NAOH MIXTURES UP TO 523 K

The densities of boric acid aqueous solutions and sodium hydroxide-sod ium berate mixtures were measured as a function of concentration, betw een 375 and 523 K at pressures close to saturation. The partial molar volumes of boric acid were obtained and it was found that they are alm ost independent of the concentration The partial molar volumes of the sodium hydroxide-sodium berate mixtures were fitted to the Pitzer equa tion for mixtures using the known parameters for NaOH. Thus, the parti al molar volume at infinite dilution and the Fitter parameters of sodi um berate could be obtained by assuming ideal mixing.