Isopiestic determination of the osmotic and activity coefficients of aqueous mixtures of NaCl and MgCl/sub 2/ at 25/sup 0/C

The osmotic and activity coefficients of aqueous mixtures of NaCl and MgCl/sub 2/ have been determined at 25/sup 0/C by using the isopiestic method. These measurements extend from low concentrations to the crystallization limits of the mixtures. They are critically compared to published isopiestic, direct vapor pressure, and emf data for this system. The data agree well with previous isopiestic data and two sets of emf values, but direct vapor pressure data are significantly discrepant. Osmotic and activity coefficients for NaCl-MgCl/sub 2/ mixtures are fairly reliably represented by both Pitzer's equations and Scatchard's neutral electrolyte equations.