SODIUM CHLORIDE SOLUTIONS AS AN ISOPIESTIC STANDARD
- 1 August 1939
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Research
- Vol. 17b (8) , 215-230
- https://doi.org/10.1139/cjr39b-032
Abstract
A method is described for the accurate determination of the vapour pressure of aqueous solutions of non-volatile salts. Solutions of two salts contained in a large silver dish are rocked in an evacuated desiccator until equilibrium is attained, then the vapour pressure of the one solution is determined from the known vapour pressure of the other. Results on the rate of attainment of equilibrium are given for various types of containers.Sodium chloride is chosen as the standard. Results are given for the system sodium-chloride–potassium-chloride at 25 °C., 30 °C., and 35 °C. Since there is a disagreement amongst the results for sodium chloride calculated from e.m.f. data and those determined from direct vapour pressure data, an arbitrarily selected vapour pressure curve is adopted. This curve is found to yield the activity coefficients of potassium chloride remarkably well. The method yields results whose accuracy is comparable with that of the best e.m.f. measurements.Keywords
This publication has 1 reference indexed in Scilit:
- The Thermodynamics of Aqueous Potassium Chloride Solutions from Electromotive Force MeasurementsJournal of the American Chemical Society, 1937