Modem developments electrolyte theory

Sections 10.16 to 10.22 give a brief description of modem developments in electrolyte theory. This is a much more difficult section conceptually and can be omitted until after the Debye-Hiickel and Bjermm theories have been assimilated. 

This system of nomenclature has withstood the impact of later experimental discoveries and theoretical developments that have since the time of Guyton de Morveau and Lavoisier greatiy altered the character of chemical thought, eg, atomic theory (Dalton, 1802), the hydrogen theory of acids (Davy, 1809), the duahstic theory (Berzehus, 1811), polybasic acids (Liebig, 1834), Periodic Table (Mendeleev and Meyer, 1869), electrolytic dissociation theory (Arrhenius, 1887), and electronic theory and modem knowledge of molecular stmcture. 

According to modem views, the basic points of the theory of electrolytic dissociation are correct and were of exceptional importance for the development of solution theory. However, there are a number of defects. The quantitative relations of the theory are applicable only to dilute solutions of weak electrolytes (up to 10 to 10 M). Deviations are observed at higher concentrations the values of a calculated with Eqs. (7.5) and (7.6) do not coincide the dissociation constant calculated with Eq. (7.9) varies with concentration and so on. For strong electrolytes the quantitative relations of the theory are altogether inapplicable, even in extremely dilute solutions. 

The integration of these three basic developments established the foundations of modem solution theory and the first Nobel prizes in chemistry were awarded to van t Hoff (in 1901) and Arrhenius (in 1903) for their work on osmotic pressure and electrolytic dissociation, respectively. 

Several physicochemical models of ion exchange that link diffuse-layer theory and various models of surface adsorption exist (9, 10, 14, 15). The difficulty in calculating the diffuse-layer sorption in the presence of mixed electrolytes by using analytical methods, and the sometimes over simplified representation of surface sorption have hindered the development and application of these models. The advances in numerical solution techniques and representations of surface chemical reactions embodied in modem surface complexation mod-... 

Section 12.9 on post 1950 modem conductance theories for symmetrical electrolytes and Section 12.10 on Fuoss-Onsager s 1957 conductance equation for symmetrical electrolytes can be omitted until earlier sections are assimilated. These two sections deal with more up to date work which is able to be formulated in a straightforward analytical equation. The development behind these theories is complex and only a brief overview of the ideas behind these theories is given. Nonetheless the Fuoss-Onsager 1957 equation has been much used to analyse experimental data. How this is carried out in practice is given in Sections 12.10.1 to... 

Chapter 2 (pVTx Properties of Hydrothermal Systems, H. R. Corti (Argentina) and I. M. Abdulagatov (Russia/ USA)) describes many theories and models developed to accurately reproduce the excess volmnetric properties and to assess the standard partial molar volmnes of the solute in aqueous electrolyte and nonelectrolyte solutions mider sub-and supercritical conditions. Most of these models and equations, particularly the equations of state, are used to compute both the thermodynamic properties of solutions and the phase equilibria. This chapter is concerned with theoretical approaches in modem chemical thermodynamics of hydrothermal systems. 

S. Arrhenius developed, in his doctoral thesis published in 1887, a theory pretty much similar to the modem concepts of 1883. He was the first to point out that eonductivity and a departure of coUigative properties from normal/expected values always occur togedier, concluding, this way, from his observations, that the two effects should have the same origin. Sueh observations could be summarized in three main points 1) in electrolyte solutions the molecules dissociate into ions spontaneously, turning the solution conductive different electrolytes exhibit different degrees of dissociation, called a, which will influence actual... 

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