The linear isopiestic relations for the saturated system (B–C–D–A2(sat)–A1) whose subsystem (B–C–D–A1) conforms to the Zdanovskii rule and the Stokes–Robinson relation

Abstract

Isopiestic measurements have been made for the systems mannitol–sorbitol–BaCl₂·2H₂O_(sat)–H₂O, mannitol–sorbitol–K₂SO_4(sat)–H₂O, mannitol–sorbitol–MgSO₄·7H₂O_(sat)–H₂O, mannitol–sucrose–BaCl₂·2H₂O_(sat)–H₂O, mannitol–sucrose–K₂SO_4(sat)–H₂O, mannitol–sucrose–MgSO₄·7H₂O_(sat)–H₂O, and sucrose–urea–NaCl_(sat)–H₂O at 298.15 K. The linear isopiestic relations for the saturated systems have been derived and compared with the present isopiestic measurements and those reported previously. For the new linear isopiestic relations to hold, the corresponding unsaturated subsystem (B–C–D–A₁) must conform to the Zdanovski rule and the Stokes–Robinson linear isopiestic relation. Under this condition, the saturated system (B–C–D–A_2(sat)–A₁) conforms to the new linear relations, irrespective of whether A₂ is a non-electrolyte or an electrolyte, a symmetrical electrolyte or an unsymmetrical electrolyte.