Ion-pairing equilibrium constant

Rotzinger then evaluated and H t as a function of the distance between the two reactant metal centers. He used the Fuoss equation to calculate the ion-pairing equilibrium constant to form the precursor complex at these internuclear distances. Assembly of these data then allowed the calculation of the self-exchange rate constants as a function of the internuclear distance in the transition state, the maximum rate being taken as the actual rate. 

E. feU (a) Using the ion-pair equilibrium constant in Appendix J, with activity coefficients = 1, find the concentrations of species in 0.025 M MgS()4. Hydrolysis of the cation and anion near neutral pH is negligible. Only consider ion-pair formation. You can solve this problem exactly with a quadratic equation. Alternatively, if you use SOLVER, set Precision to le-6 (not le-16) in the SOLVER Options. If Precision is much smaller. SOLVER does not find a satisfactory solution. The success of SOLVER in this problem depends on how close your initial guess is to the correct answer. 

Fuoss adopted the concept of the electrostatic contact ion-pair [60] and considered the anion as a point charge that may also penetrate the cation-conducting sphere of radius a. The final expression for the ion-pairing equilibrium constant,... 

The solvation and correlation are taken into account, thereby departing from the RPM. The dependence of solvation on distance was recently investigated [67], The expression of the ion-pairing equilibrium constant is analogous to that developed by Gilkerson or by Fuoss. Again, the solvation parameter avoids the linearity of In /Teh with Me. 

It was also more interesting to observe that the valne of hydrophobic ion-pairing equilibrium constant runs counter to predictions of a purely electrostatic approach since it increases with increasing size of the pairing ion [107,109,112] for both organic and... 

The chromatographic estimate of ion-pairing equilibrium constant via IPC [87,114] will be thoroughly detailed in Chapter 3 (Section 3.1.2) and will confirm that separative techniques are particularly valuable for ascertaining the nature of hydrophobic ion-pairing. 

From these observations some aspects of chain growth peculiar to zwitterionic propagating species can be deduced. It seems that the proportion of cyclics to long zwitterionic chains is strongly influenced by the dielectric properties of the medium. The most logical explanation is a shift in the inter-intramolecular ion pair equilibrium constant. 

Obviously, the dieleetrie behavior of systems with ion pairing is much more complex than those without it. The presence of the ion pair gives the solution a higher permittivity at lower frequencies than it otherwise would have. This feature is important in understanding the equilibrium properties of these solutions. The permittivity data for the low-frequency process may be used to determine the ion pairing equilibrium constant and the rate constants for formation and breakup of this species. Thus, dielectric relaxation experiments in electrolytes provide valuable information about ion association equilibria. 

Table IV. Mixed iso-HMTT/PMDT Chelated Na+C10H8 Relative Intensities and Ion-pair Equilibrium Constant...

SerH = the zwitterion of serine, is the anation rate constant, and is the ion-pair equilibrium constant between SerH and [Co]. Reaction rates in different ethanol-water mixtures reach a limit at high ligand concentrations and increases as the concentration of the organic component in the medium increases, while the reverse is true for k. The reaction is catalyzed by NOJ and the rate increases with pH within the quoted range. A mechanism involving ion-pair formation followed by dissociative interchange of the outer-sphere complex with the product is proposed. 

Table 12.5 gives data for the second-order region for anation of [Ni(H20)6], which is hypothesized to occur via a preassociation mechanism. The second-order rate constant, k2Ki, is the product of the ion-pair equilibrium constant, Ki, and the rate constant, k2 (Section 12.3.4) ... 

Aqueous solutions of alkali metal salts exhibit almost no association, in contrast to solutions of 2,2 electrolytes, such as CdS04. Solutions of low permittivity contain ion pairs (equilibrium constant Ka), triple ions (equilibrium constant ATt), and higher associates, such as... 

Raman in CO stretching region temp, variation of complex infrared band envelope reveals presence of two kinds of anion environment and permits spectra to be divided into four band components study made of the variation of these band components with concn. [0.03-0.0007M] and temp. [29 to —42°] anion sites identified as solvent-separated ion pairs and contact ion pairs CO stretching frequency assignments are Ft = 1886, Ai = 2005 for the solvent separated ion pair and Ai = 1855, 2005, E = 1898 cm-> for the contact ion pair equilibrium constant for conversion of contact pairs to solvent separated pairs at 29° was K = 0.45 with AH = 3.7 Kcal and AS = 14 eu... 

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