Self-dissociation degree

The next issue that arises from the weak acidity of carbon acids involves the degree of self-dissociation. In Eq. 3, the equihbrium constant is determined by measuring the concentration of the four species in the equation, but this requires that the carbon acid self-dissociates to an extent that a measurable quantity of the carbanion is formed. Again, because carbon acids are generally weak, this requirement often is not met and therefore another type of equilibrium measurement... 

The high degree of self-dissociation of water at high densities leads to catalysis of water elimination from alcohols and the formation of double bonds. In the case of tert-butanol [25], complete conversion to isobutene is achieved in 30 s at subcritical temperatures without addition of acids. In other cases, such as the elimination of water from ethanol [26], propanol [27, 28], glycerol [29], glycol [30], fructose [31,... 

Perceived difference between ionic melts and room-temperature molecular solverrts can be related to Umitations of the solvosystem concept. The division of substances into acids and bases is based on their reactions with the products of the molecular solvent selfdissociation, and the degree of this self-dissociation in ptrre solvent is considered negligible. On the contrary, an ionic melt is the case of completely ionized solvent, and this is just the fact that does not give possibiUty to apply the classic solvosystem concept fraitfully for studies of acid-base irrteraction in this kind of liquid media. 

If the solvent is not protogenic but protophilic (acetone, dioxan, tetrahydrofuran, dimethylformamide, etc.), self-ionization obviously does not occur. Consequently, the dissolved acids are dissociated to a greater or lesser degree but dissolved bases do not undergo protolysis. Thus, there can exist only strong acids but no strong bases in these solvents. The pH is not defined for a solution that does not contain a dissolved acid (i.e. in the pure solvent or in the solution of a base). The pKA value can be defined but not... 

By surface science techniques, Mullins and Overbury showed that the presence of reduced ceria might create new active sites for NO dissociation [82], The degree of decomposition is increased and the onset temperature for decomposition is reduced when Rh is supported on reduced ceria (Rh/CeOj compared to Rh on oxidized ceria (Rh/Ce02) NO dissociation being self-inhibiting. 

It would be easy to draw a cynical conclusion from these data which show that coins of lower denomination—namely those most likely to be used by the poorer people—were debased to a greater degree than the two-peso pieces which were used in major transactions by the revolutionary groups and were known in the American border states as the Guerrero dollar. But care should be taken to dissociate these apparently self-serving economic manipulations as shown through the coinage from the main thrust of the Zapatista revolutionaries. Zapata s coalition was... 

The theory is deficient in many respects, e.g. in any real case the degree of surface charge dissociation will be afiected by the presence of a neighbouring surface. This can be taken into accoimt in a self-consistent manner [22, 27]. 

An important conclusion has been arrived at by McBam and Kam (loc at) in a paper with the following self-explanatory title The effect of salts on the vapour pressure and degree of dissociation of acetic acid in solution An expenmental refutation of the hypothesis that neutral salts increase the dissociation constants of weak acids and bases ... 

Much less is known about micellar charge and counterion binding in the case of bile salts. Based on the result of ionic self-diffusion measurements [20,163,173], conductance studies [17,18,187], Na, and Ca activity coefficients [16,19,144,188,189] and NMR studies with Na, Rb and Cs [190], a number of generalities can be made. Below the operational CMC, all bile salts behave as fully dissociated 1 1 electrolytes, yet interionic effects between cations and bile salt anions decrease the equivalent conductance of very dilute solutions [17,18,187]. With the onset of micelle formation, counterions become bound to a small degree values at this concentration are about < 0.07-0.13 and are not greatly influenced by the species of monovalent alkali cations [163,190]. At concentrations above the CMC, values remain relatively constant to 100 mM in the case of C and this... 

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