Debye-Huckel laws

At low ionic strengths, the V7 term in the denominator becomes negligible, so (1 + i>V7) tends to unity, yielding the limiting Debye-Huckel law. 

Fig. 16. Text of the Debye-Huckel law and evaluation of for the partition measure-...

Knowing (Zn ) from the Nemst equation and the activity coefficient y for the zinc cation from the Debye-Huckel law, we can therefore calculate the concentration, [ZnS04], from equation (3.10). 

I. 46. The magnitude of the coefficient reflects the electric charge distribution of the ionic species. A 0.1 molal solution of Al2(S04)3 has an activity coefficient of only 0.035. It should also be noted that, in dilute solutions, activity coefficients of electrolytes decrease in magnitude with increasing concentration. A minimum is reached and the coefficient then increases with concentration. See Activity Debye-Huckel Law Biomineralization... 

The Debye-Huckel Theory The Finite-Ion-Size Model. If the approximation of the point charge is removed, the extended form of the Debye-Huckel law is obtained ... 

Next, one returns to Eq. (4.10.5), which was derived, as should be noted, without recourse to the Debye-Huckel Law. This relation may be rewritten as... 

The theory of concentrated electrolyte solutions is still in an undeveloped form. Various corrections have been suggested to make the Debye-Huckel law valid for more concentrated solutions, but these are either empirical or at best on an uncertain theoretical basis and we shall not develop them further. 

Limiting laws in science are tho,se that hold under limiting conditions such as dilute solutions. In addition to Beer s law, other limiting laws in chemistry include the Debye-Huckel law (see Chapter 10) and the law of independent migration, which describes the conductance of electricity by ions. 

The solubility product is calculated as = y which is correct only if Z,p = 4c . The mean activity coefficent was obtained from the limiting Debye-Huckel law as y = 0.866. This value is consistent with the solubility data only if the concentration refers to Ag2Se04 and is expressed in mol-L (M). The solubility product is therefore most likely 4 times larger than reported. 

Log Yj may be evaluated with extended Debye-Huckel law, but for most purposes, it is small and can be neglected, so that... 

It would seem that substitution of E and Q values would allow the computation of the standard redox potential for the couple, However, a problem arises because the calculation of Q requires not only knowledge of the concentrations of the species involved in the cell reaction but also of their activity coefficients. These coefficients are not usually available, so the calculation cannot be directly completed. However, at very low concentrations, the Debye-HUcke limiting law for the coefficients holds. The procedure then is to. substitute the Debye-Hiickel law for the activity coefficients into the specific form of the Nemst equation for the cell under investigation and carefully examine the equation to determine what kind of plot to make of the E[ b ) data so that extrapolation of the plot to zero concentration, where the Debye-Huckel law is valid, gives a plot intercept that equals See Section 7.8 for the details of this procedure and an example for which the relevant graph involves a plot of + (2RT/F) In b against... 

For a dilute solution of a strong electrolyte, this gives the limiting Debye-Huckel law. 

Under what conditions does the extended Debye-Huckel law, equation 8.52, become the Debye-Hiickel limiting law ... 

If the ion radius, a, is put equal to zero in the extended Debye-Huckel law the equation repiesenting the simple Oebye-Huckel limiting law is regained. 

Because of the unusual concentration dependence of 0 at high dilution and because no simple limiting behavior such as the Debye-Huckel law for electrolytes was available, the integration of Equation (11) was conducted from an arbitrarily chosen concentration, Me = 10 equiv./kg H2O, where the activity coefficient, yc, was defined as unity and the polyelectrolyte osmotic coefficient was approximated by its limiting value 00 = 0.2. Thus,... 

---