Application of Irreversible Thermodynamics to Transport Processes in Binary Electrolyte Solutions

Theory of irreversible thermodynamics has been applied to isothermal transport processes in binary electrolyte solutions. Relations are presented which express the commonly measureable transport quantities in terms of Onsager transport and inverse frictional Rik coefficients. Relations for Lik and Rik coefficients are presented in terms of the experimental quantities, ti, A and Dv. Equivalent conductances of rubidium and caesium chlorides and diffusion coefficients of rubidium chloride have been measured in the concentration range 0-3M. These have been combine with the remaining transport, activity and density data which existed in the literature and the Lik and Rik coefficients obtained. Literature from 1930 to 1970 has been surveyed for transport numbers, equivalent conductances, diffusion and activity coefficients for 1:1, 1:2, 2:1 and 2:2 electrolyte solutions in aqueous media. Results, for twenty eight systems for which data was also complete, have been calculated as a basis of comparison. The relative sizes of these coefficients have been discussed in terms of ion solvation and water structure. An interpretation of the physical significance of frictional coefficients is developed for completely dissociated as well as associated 1:1 electrolytes. Association in alkali metal chlorides potassium and silver nitrate solutions has been studied by the conductance theories of Pitts and Fuoss. Abnormalities in rubidium-chloride and caesium-chloride interactions have been ascribed to ion association and the true interionic friction coefficient calculated and compared with those for the completely dissociated alkali metal chlorides. The correction reduces the inter- ionic friction from its apparent value calculated on a stoi-cheiometric basis and places the salts in a rational order. The significance of q12, the degree of coupling between mobile species, has been developed as a suitable parameter for comparison of a variety of electrolytes of different valence types