Sodium bicarbonate and carbonate ion pairs and their relation to the estimation of the first and second dissociation constants of carbonic acid

1970 ◽  
Vol 74 (13) ◽  
pp. 2726-2728 ◽  
Author(s):  
Francis S. Nakayama
1987 ◽  
Vol 40 (7) ◽  
pp. 1201 ◽  
Author(s):  
W Mizerski ◽  
MK Kalinowski

An empirical relation describing the effect of solvent on the dissociation constant ( Kd ) of ion pairs is described. An equation of the form pKd = apKso + bD-1 + c ( Kso and D stand for the solubility product of a given salt and for the electric permittivity of a solvent, respectively) has been tested with 13 sets of experimental data for salts containing tetraalkylammonium and alkali-metal cations. A successful correlation was obtained in 100% of the cases considered.


Osmotic coefficient data for the sulphates of Mg, Ca, Zn, Ni and Cu in aqueous solution have been analysed to obtain the dissociation constants (d.c.) of ion pairs, triplets and quadruplets, as well as information on their state of hydration. The d.c.’s of the sulphate ion pairs, though of similar magnitude, show distinct individualities, and the trend is similar to that of the d.c.’s calculated for the nitrates of di-valent ions, though the d.c.’s of the latter are about 200 times larger. The d.c.’s of the ion triplets show no correlations, but their absolute values are similar to those calculated from the theory of Fuoss & Kraus (1933, 1935) based on electrostatic considerations. The hydration parameters of the associated sulphates (both pairs and triplets), as characterized in the linear (statistical) terms of the osmotic coefficients, are only slightly smaller than those of the fully dissociated electrolytes, indicating that there is only little loss of hydration water in the process of association, in spite of the heavy hydration of the divalent cations and the relatively close approach of the sulphate ion. The complete analysis of the osmotic coefficient curves makes it possible to calculate the absolute values of the activity coefficients of the divalent sulphates (previously not known to any accuracy).


2000 ◽  
Vol 27 (2) ◽  
pp. 229-232 ◽  
Author(s):  
Kitack Lee ◽  
Frank J. Millero ◽  
Robert H. Byrne ◽  
Richard A. Feely ◽  
Rik Wanninkhof

1927 ◽  
Vol 10 (5) ◽  
pp. 703-723 ◽  
Author(s):  
Ralph S. Lillie

1. Comparison of the rates of activation of unfertilized starfish eggs in pure solutions of a variety of parthenogenetically effective organic acids (fatty acids, carbonic acid, benzoic and salicylic acids, chloro- and nitrobenzoic acids) shows that solutions which activate the eggs at the same rate, although widely different in molecular concentration, tend to be closely similar in CH. The dissociation constants of these acids range from 3.2 x 10–7 to 1.32 x 10–3. 2. In the case of each of the fourteen acids showing parthenogenetic action the rate of activation (within the favorable range of concentration) proved nearly proportional to the concentration of acid. The estimated CH of solutions exhibiting an optimum action with exposures of 10 minutes (at 20°) lay typically between 1.1 x 10–4 M and 2.1 x 10–4 M (pH = 3.7–3.96), and in most cases between 1.6 x 10–4 M and 2.1 x 10–4 M (pH = 3.7–3.8). Formic acid (CH = 4.2 x 10–4 M) and o-chlorobenzoic acid (CH = 3.5 x 10–4 M) are exceptions; o-nitrobenzoic acid is ineffective, apparently because of slow penetration. 3. Activation is not dependent on the penetration of H ions into the egg from without, as is shown by the effects following the addition of its Na salt to the solution of the activating acid (acetic, benzoic, salicylic). The rate of activation is increased by such addition, to a degree indicating that the parthenogenetically effective component of the external solution is the undissociated free acid. Apparently the undissociated molecules alone penetrate the egg freely. It is assumed that, having penetrated, they dissociate in the interior of the egg, furnishing there the H ions which effect activation. 4. Attention is drawn to certain parallels between the physiological conditions controlling activation in the starfish egg and in the vertebrate respiratory center.


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