Experimental determination of the volumetric properties of NaCl solutions to 253 K

The densities of 0.00858-6.0141 mol(.)kg(-1) NaCl solutions were determined between 253 and 293 K with a capillary-tube densitometer. Among the data w ere the first density determinations of supercooled NaCl solutions. The gre atest inaccuracy of the measured densities for the entire data set was 200 mug(.)cm(-3). Our densities were close to those calculated with the equatio n of state for the NaCl-H2O system of Archer. Apparent molal volumes of NaC l(aq) were calculated and fitted to the Pitzer equations, yielding estimate d apparent molal volumes at infinite dilution and Pitzer volumetric paramet ers to 258 K. The values of these parameters from 273 to 298 K were in good agreement with the data of Rogers and Pitzer. From our experimental data w e were able to calculate densities of very dilute to saturated sodium chlor ide solutions at temperatures down to 258 K.