Dependence of the Second Virial Coefficient of Aqueous Solutions of Small Non-Electrolytes on Partial Molar Volume and Molecular Weight of the Solutes

Abstract

The osmotic pressures of aqueous solutions of small non-electrolytes, namely ethane-1,2-diol, propane-1,2,3-triol, sucrose and raffinose , were found to be expressible by quadratic equations of the molar concentration, which indicate that these aqueous systems involve no term higher than the second virial coefficient A₂. Analysis has shown that A₂ mainly does not arise from non-ideality of the aqueous solutions, but its magnitude depends on the partial molar volume of the solute, more precisely on the molecular weight or van der Waals radius or volume of the solute in the aqueous solution.