ISOPIESTIC MEASUREMENTS OF OSMOTIC AND ACTIVITY COEFFICIENTS FOR SYSTEMS HCLO4-LICLO4-H2O HCLO4-NACLO4-H2O AND LICLO4-NACLO4-H2O

Isopiestic measurements of the osmotic coefficients are presented for the systems HClO4-LiClO4-H20, HClO4-NaClO4-H2O, and LiClO4-NaClO4-H2O. Parameters obtained from these results are used to derive the activity coefficients in the mixtures. Estimates of the activity coefficients in the mixtures may be made from information on the limiting two-component systems with an error of 7% or less at concentrations up to 5 m. The systems HClO4-LiClO4-H2O and LiClO4-NaClO4-H2O obey Harned's rule for both components reasonably well over the concentration range studied. For the system HClO4-NaClO4-H2O the deviations are greater, especially at the higher concentrations.