Debye-Hiickel parameters

Table 7.1 Debye-Hiickel parameters for the activity coefficient, volume, enthalpy, and...

Here = 2.303T/3, where A is the Debye-Hiickel parameter. 

Helgeson, H. C. and D. H. Kirkham, 1974, Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures, II. Debye-Hiickel parameters for activity coefficients and relative partial molal properties. American Journal of Science 274, 1199-1261. 

A is a Debye-Hiickel parameter (cf. Appendix II) and I is the ionic strength. Pitzer found that binary interaction parameter Xdepends on ionic strength and may conveniently be expressed as ... 

Plotting ixbase VS. pH gives a sigmoidal curve, whose inflection point reflects the apparent base-pAi, which may be corrected for ionic strength, I, using Equation 6.11 in order to obtain the thermodynamic pATa value in the respective solvent composition. Parameters A and B are Debye-Hiickel parameters, which are functions of temperature (T) and dielectric constant (e) of the solvent medium. For the buffers used, z = 1 for all ions ao expresses the distance of closest approach of the ions, that is, the sum of their effective radii in solution (solvated radii). Examples of the plots are shown in Figure 6.12. 

The thickness of the diffuse-charge region is given by K 1,i.e., the Debye-Hiickel parameter (Section 6.6.4). Thus, if the fluid velocity is v at the distance k" then the velocity gradient is given by... 

Dependence of Debye-Hiickel parameter on temperature and type of... 

Debye-Hiickel parameter, estimated here as k = y/ c/3 A. 1 (assuming the dielectric constant of the solvent medium inside the double layer is 80). valence of charges (= 1) electronic charge... 

Debye-Huckel parameter — The Debye-Hiickel parameter k of an electrolyte solution is calculated as... 

Debye-Hiickel parameter k (the Debye length), which has the dimension of length, serves as a measure for the thickness of the electrical double layer. Figure 1.5 plots the... 

Consider a charged plate with arbitrary surface potential ij/o in a symmetrical electrolyte solution of valence z and Debye-Hiickel parameter k. We take an x-axis perpendicular to the plate surface with its origin at the plate surface so that the region x > 0 corresponds to the solution phase while the region x < 0 to the plate interior. Equation (1.37) (or Eq. (1.38)) for the potential distribution ij/(x) around the surface in the region far from the surface, that is, at large kx, takes the form... 

The asymptotic expression for the potential of a spherical particle of radius a in a symmetrical electrolyte solution of valence z and Debye-Hiickel parameter k at a large distance r from the center of the sphere may be expressed as... 

Note that Eq. (2.58) is twice the Coulomb potential j/ r) = qe /An Zor produced by a point charge q at distances r from the charge in an electrolyte solution of relative permittivity and Debye-Hiickel parameter k. This is because we have assumed that there is no electric field within the plate X < 0. 

We again see that in the limit of small Ka, the effective Debye-Hiickel parameter is given by Eq. (3.52) and that in the limit of large Ka, rod-like zwitterions behave like monovalent electrolytes of concentration nJ2 and the effective Debye-Hiickel parameter is given by Eq. (3.55). 

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