Hydrolysis constants, and

Table 6.6 Hydrolysis constant and degree of hydrolysis for hydrolysis of salts.

S. Kobayashi, S. Nagayama, T. Busujima, Lewis Acid Catalysts Stable in Water. Correlation between Catalytic Activity in Water and Hydrolysis Constants and Exchange Rate Constants for Substitution of Inner-Sphere Water Ligands J. Am. Chern. Soc 1998, 120, 8287-8288. 

Table 1 Hydrolysis constants and exchange rate constants for substitution of inner-sphere water ligands...

Simple multivalent cations such as Mg2+ and Al + are ineffective in charge reversal for coagulation (62) experiments and in activation for froth flotation (35). The related positive hydroxo complexes do function as coagulants and flotation activators and hence must be specifically adsorbed. By knowing the appropriate hydrolysis constants and the most effective species (in flotation systems apparently M+z(OH)Vi and in coagulation, polynuclear complexes), one can predict the pH range in which each cation can be expected to adsorb strongly. 

A good deal of work will have to be done to extract species information from the apparent equilibrium constants that have been reported for about 500 reactions. Beyond that, use can be made of analogies with known reactions for example, the various ribonucleotide phosphates (AMP, GMP, CMP, UMP, and dTMP) are believed to have the same hydrolysis constants and pKs. Beyond that, the group additivity method (Alberty, 1998c) can be used to estimate thermodynamic properties. 

The equilibrium constant of this process is called the hydrolysis constant, and can be written as ... 

There are many ways to measure the reactivity index, and all of them are feasible in such a study. By finding one that works—i.e., gives significant statistics in Equation 1—statements may be formulated regarding possible mechanisms. In this type of work, it must be remembered that it is not valid to imply causality to a correlation. However, from a pragmatic point of view, it is possible to set up models that can be tested by further synthesis. The measurements used for the reactivity index in the following examples include hydrolysis constants and molecular orbital calculations. 

A 0.046 N solution of the potassium salt of a weak monobasic acid was found to have a pH of 9.07 at 25° calculate the hydrolysis constant and degree of hydrolysis of the salt, in the given solution, and the dissociation constant of the acid. 

Hydrogen migration. 709 Hydrolysis constants, and charge-size functions, 328 Hydrometallurgy. 382-383, 384 Hydron, and proton, 318, A49 Hypho structures, 798-800, A77... 

Figure 10.28 Correlations between (a) cation hydrolysis constants and TL intrinsic adsorption constants for cations adsorbed by HFO (goethite and amorphous...

H2O and U(OH)4(am) = U(OH)4. Reprinted with permission from Inorg. Chem. 29 260-64, D. Rai et al., Uranium (IV) hydrolysis constants and solubility product of UO2 j H20(am). Copyright 1990 American Chemical Society. 

Examples of correlations between stability constants of surface complexes (calculated using different adsorption models, cf. Chapter 5) on the one hand, and the first hydrolysis constant and other constants characterizing the stability of solution complexes on the other are more munerous than the studies of correlations involving directly measured quantities. It should be emphasized that there is no generally accepted model of adsorption of ions from solution, and stability constants of surface complexes are defined differently in particular models, thus, the numerical values of these constants depend on the choice of the model. Moreover, some publications reporting the correlations fail to define precisely the model. 

I min correlations between hydrolysis constant and surface complex formation... 

The values obtained for the catalytic coefficients, the hydrolysis constants, and the ionization constants at absolute temperature, T, are given by the equations ... 

In a similar way it can be shown that for the salt of a strong and a weak base, the product of the hydrolysis constant and the base strength is equal to... 

Note that liquid water concentration has already been incorporated into the hydrolysis constant and that Khc is identical to the Henry s law coefficient for carbon dioxide, Wco2-... 

In the second step, with the hydrolysis constants and the specific interaction parameter for ZrOH" and for Zr3(OH) fixed to the values optimised as detailed above, the equilibrium constants and interaction parameter for all other species in the overall hydrolysis model were obtained by a global fit of the potentiometric, solubility, solvent extraction and ion exchange data mentioned above. The fit was extended to the determination of equilibrium constants for heterogeneous reactions ion exchange constants, solubility constants and liquid/liquid distribution coefficients. The fit was based on a preselection of the stoichiometries of dominant species which included invariably the species Zr(OH)4(aq), Zr ) ), Zr (OH)Jj and Zr4(OH)i6(aq) and various other mono-, di-, tri- and tetravalent species to improve the fit. The potential formation of chloride complexes of Zr was considered for chloride containing solutions, using the stability constants determined in Section V-4. If all fitted results were found insensitive to the equilibrium constants of a given species, the respective species was removed from the list of species. 

SOL] Solovkin, A. S., Determination of hydrolysis constants and of formation constants of Zr with nitrate- and chloride- ions by extraction methods, Russ. J. Inorg. Chem., 2, (1957), 216-236. Cited on pages 117, 153, 197, 198, 199, 252, 256, 257. 

Figure VII-15 Solubility data for Th02(am, hyd) in 0.5 M NaC104 a) from [1989MOO] and b) from [19940ST/BRU] (filled squares eaibonate-free solution open squares under C02(g) atmosphere which has, however, no effect on the speciation at pH < 4.5). The solubility constant and aqueous speciation are calculated using the hydrolysis constants and SIT coefficients selected in the present review...

Figure VII-16 Solubility of thorium hydroxide determined by Higashi [1959HIG] at room temperatnre from oversaturation after 1, 3, 7, and 100 days. The solnbihty and speciation lines are calcnlated with the hydrolysis constants and SIT coefficients selected in this review, logj,...

Figure A-12 Solubility of thorium hydroxide determined by Nabivanets and Kudritskaya [1964NAB/KUD] at 17°C in 0.1 M NaC104. The ealculated lines are based on the hydrolysis constants and ion interaction coefficients selected in this review,...

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