Bases acid-base strengths

Flood, H., Forland, T. Roald, B. (1947). The acidic and basic properties of oxides. III. Relative acid-base strengths of some polyacids. Acta Chemica Scandinavica, 1, 790-8. 

Acid-base strength in MejSO The chemistry of MejSO (general) Coordination compounds of sulfoxides The chemistry of MejSO (inorganic)... 

Using the multisite complexation model (MUSIC), ° the surface of palladium oxide has been modeled providing useful data on the nature, number, and the acid-base strength of the hydroxyl groups present on the different faces (111) and (10 0) of... 

An inner-sphere complex is formed between Lewis acids and bases, while an outer-sphere complex involves a water molecule interposed between the acid and the base. A hard Lewis acid is a molecular unit of small size, high oxidation state, high electronegativity, and low polarizability whereas a soft Lewis acid is a molecular unit of relatively large size, characterized by low oxidation state, low electronegativity, and high polarizability. Based on this characterization, hard bases prefer to complex hard acids, and soft bases prefer to complex soft acids, under similar conditions of acid-base strength. 

Relationships of acid-base strengths are in fact relationships between free energies of reaction in terms of the thermodynamic... 

One of the fundamental questions in considerations of acid-base strengths in solution of molecules involving mesomerism is the rela-... 

In this chapter, a brief summary of studies that made use of calorimetry to characterize compounds comprising group IIIA elements (zeolites, nitrides, and oxides catalysts) was presented. It was demonstrated that adsorption microcalorimetry can be used as an efficient technique to characterize the acid-base strength of different types of materials and to provide information consistent with the catalytic data. 

It is important not to confuse acid/base strength, which depends on the degree of ionization, with concentration. Concentration measures how much acid or base is in... 

Acid—Base Strength Hardness and softness refer to special stability of hard-hard and soft-soft interactions... 

The aqueous solubility of the salt of a drug has also been considered a function of the acid-base strength and aqueous solubility of the counterion employed in the salt formation (Nelson, 1957). As an example, choline itself is considered strongly basic because of the hydroxide counterion,... 

Acid/Base Strength of Conjugate Acid-Base Pairs... 

Acids and bases react to give salts and (usually) water. That is one definition of a salt. So, when we say salt solution, we are really talking about solutions that contain the conjugate acid or base of some other acid or base. The pH of a salt solution depends on the acid/base strength of the acid or base from which it was derived. There are three permutations on the problem salts of strong ac-ids/bases, salts of weak acids, and salts of weak bases. Let s consider them each in turn. 

A titration curve is a plot of a solution s pH charted against the volume of an added acid or base. Titration curves are obtained if a pH meter is used to monitor the titration instead of an indicator. At the equivalence point, the titration curve is nearly vertical. This is the point where a rapid change in pH occurs. In addition to determining the equivalence point, the shape of titration curves may be interpreted to determine acid/base strength and the presence of a polyprotic acid. 

Hard bases prefer to complex hard acids and soft bases prefer to complex soft acids, under comparable conditions of acid-base strength. 

A thermochemical method for comparing pKa values of weak acids in DMSO has been described by Arnett et al. (1973). A linear relationship is observed between AGf and AHf for 30 weak acids in DMSO over a range of 20 pKa units. Thus AHf, the enthalpy of ionization in DMSO, is a useful guide to relative acid/base strength (Arnett and Scorrano, 1976). The relationship implies, of course, that AS° is linearly related to AHf. Correlations have been drawn between acidities in DMSO and intrinsic gas-phase acidities (Arnett et al., 1975 Bordwell et al., 1975). 

No rigorous practical definition of acid strength exists outside of very dilute aqueous solutions where activity coefficients can be assumed to be unity. Each method of measuring the acid strength of surface sites is liable to give somewhat different answers, the results being qualitative at best. The dielectric constant of the medium, in which the acid or base probe is used influences the measured acid-base strength. 

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