Osmotic and activity coefficients of {yNaH2PO4+(1−y)Na2SO4}(aq) at the temperature 298.15 K

The osmotic coefficients of the mixed electrolyte solution {yNaH2PO4+(1−y)Na2SO4}(aq) have been measured by the isopiestic method, at the temperature T=298.15 K. The activity coefficients of NaH2PO4 and Na2SO4 were calculated by Scatchardʹs neutral-electrolyte method and by Pitzer and Kimʹs treatment for mixed-electrolyte solutions. The Scatchard interaction parameters are used for calculation of the excess Gibbs energy as a function of ionic strength and ionic-strength fraction of NaH2PO4. Also, the Zdanovskiiʹs rule of linearity is tested.