Debye-Hiickel theory of electrolytes

Use these data and the Debye-Hiickel theory of electrolyte nonideality to criticize or defend the following proposition Indifferent electrolytes always inhibit the rates of ion combination reactions because the activity coefficients are fractions. The data for CTABr show an enhancement of rate so this cannot be due to an activity effect. In these data, the k s for pure water and aqueous NaCl are essentially identical, so no activity effects operate in the absence of micelles either. 

There are many situations in which the spherically symmetrical case is specifically invoked, as in the Debye-Hiickel theory of electrolyte nonideality, for example. We consider situations for which this is the case in Chapter 12. For now, however, we consider the potential distribution adjacent to a planar wall that carries a positive charge. 

This same relationship is the starting point of the Debye-Hiickel theory of electrolyte nonideality, except that the Debye-Hiickel theory uses the value of V2 p required for spherical symmetry. It is interesting to note that Gouy (in 1910) and Chapman (in 1913) applied this relationship to the diffuse double layer a decade before the Debye-Hiickel theory appeared. 

Every chemist at one time or another has encountered the Debye-Hiickel theory of electrolyte solutions. It is essential to understand the nature of ions in ho-... 

So here, the term theory will be used in a way that embraces the typical named theories of chemistry such things as molecular orbital theory, valence shell electron pair repulsion theory, transition state theory of reactions, and Debye Hiickel theory of electrolyte solutions. No decisive distinction will be made between theory, model, and other similar terms. But there is one distinction that we do make. The term theory is considered in an epistemological sense—as an expression of oin best knowledge and belief about the way chemical systems work. 

Debye Length A parameter in the Debye—Hiickel theory of electrolyte solutions, k-1. For aqueous solutions at 25 °C, k = 3.288y7 in reciprocal nanometers, where I is the ionic strength of the solution. The Debye length is also used in the DLVO theory, where it is referred to as the electric double-layer thickness. See also Electric Double-Layer Thickness. 

Thus at a distance 1 Jk the potential has dropped by a factor of (1/e). This distance may be used as a measure of the extension of the double layer and is often loosely called the thickness of the double layer. According to the theoretical equations it has the value /k = [ekT/e l.CizlY and is identical with the parameter introduced in the Debye-Hiickel theory of electrolytes in which /k is identified with the radius of the ionic atmosphere. Of particular importance in colloid science is the fact that the thickness of the... 

Finally we shall consider the effect of ionic strength s on the intermolecular potential. The potential of an ion as a function of ionic strength can be calculated from the Debye-Hiickel theory of electrolytes for low ionic strengths (<10 Mforl l electrolytes and even smaller concentrations for higher valences) and is [1]... 

Huckel began his quantum theoretical studies of chemical bonding following postdoctoral work at several locations, the most important one being Zurich, where he developed together with his Ph.D. advisor Peter Debye the well-known Debye-Hiickel theory of electrolytic... 

The velocity of migration of individual ions is characterised by mobility. The mobility of ions directly influences the diffusion constant, and indirectly the reaction rate, through its effect on diffusion. For the connection between the theory of ion reactions and the Debye-Hiickel theory of electrolytes see, for example, Moelwigh-Hughes (1971). 

Onsager, Lars (1903-76) Norwegian-born American chemist. Onsager made several important contributions to theoretical chemistry and physics. In 1926 he improved on the Debye-Hiickel theory of electrolytes by taking the Brownian motion of ions into account. He subsequently investigated the dielectric constants of matter that contains polar molecules. In 1931 he published fundamental work on nonequilibrium thermodynamics. He was awarded the 1968 Nobel Prize for chemistry for this work. 

Poisson-Boltzmann equation — The Poisson-Boltz-mann equation is a nonlinear, elliptic, second-order, partial differential equation which plays a central role, e.g., in the Gouy-Chapman ( Gouy, Chapman) electrical double layer model and in the Debye-Hiickel theory of electrolyte solutions. It is derived from the classical Poisson equation for the electrostatic potential... 

The publication in 1948 of a monograph by Verwey and Overbeek detailing work done by them and others during World War II on the application of the PB equation, and, in particular, the Gouy-Chapman version of it, to the study of colloids has proved to be as important as the initial publications by Gouy and Chapman and Debye and Hiickel. This study laid the foundation for the modern study of colloids and has served as the primary guidepost for most of the work described here. Today, the PB equation, and in particular the Debye-Hiickel (DH) linearized approximation, forms the foundation for modern descriptions of electrolyte and colloid theory. New theories are compared with and often derived from the nonlinear Poisson-Boltzmann equation and in the appropriate limits reduce to the DH result. As has been shown by modern statistical methods, the Debye-Hiickel theory of electrolyte solutions is analogous to the lowest-order harmonic approximation in potential theory. ... 

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