Thermodynamics of Transfer of Sodium Chloride from Water to Aqueous Sucrose at 25 degrees C

Enthalpies of transfer of sodium chloride over the mixed-solvent range from pure water to mole fraction sucrose X(3) = 0.05 ( 50 wt.%) were determined calorimetrically at 25 degrees C. These were combined with free energies of transfer at constant molality (per 1000 g of mixed solvent) calculated from isopiestic activity coefficients to yield negative entropies of transfer. The positive free energy is approximately a linear function of X(3), and the negative enthalpies show that the free energies and activity coefficients of NaCl increase with temperature. The enthalpy behavior of NaCl in aqueous hydrogen peroxide and the urea is very similar to that in the present study, indicating the possibility of rough colligative effect for such systems.