Activities and Concentrations of Nonelectrolytes in Dilute Liquid Solutions Study of the Osmotic Pressure

Abstract

The chapter mentions the study of the osmotic pressure of dilute liquid solutions of nonelectrolytes. The study is performed within the framework of the grand ensemble. Through a reasoning analogous to that followed for the study of the activities of gases, a mathematical relation between the activity of the solute and its density number is set up in the case of a binary solution solute–solvent. It is valid for dilute solutions. In its expression intervene parameters related to the virial coefficients, so-called coefficients of the osmotic pressure virial. The theory is due to McMillan–Mayer. It entails the introduction of a new activity coefficient. The developments constituting the theory take into account not only the interactions solute–solute but also the solute–solvent ones and those exerting between solvent molecules.

The reasoning developed here constitutes a model for that followed later devoted to the study of solutions at constant temperature and pressure.