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The Hammett acidity function (H 0) is a measure of acidity that is used for very concentrated solutions of strong acids, including superacids.It was proposed by the physical organic chemist Louis Plack Hammett [1] [2] and is the best-known acidity function used to extend the measure of Brønsted–Lowry acidity beyond the dilute aqueous solutions for which the pH scale is useful.
The strength of a weak organic acid may depend on substituent effects. The strength of an inorganic acid is dependent on the oxidation state for the atom to which the proton may be attached. Acid strength is solvent-dependent. For example, hydrogen chloride is a strong acid in aqueous solution, but is a weak acid when dissolved in glacial ...
On the other hand, if a chemical is a weak acid its conjugate base will not necessarily be strong. Consider that ethanoate, the conjugate base of ethanoic acid, has a base splitting constant (Kb) of about 5.6 × 10 −10, making it a weak base. In order for a species to have a strong conjugate base it has to be a very weak acid, like water.
A strong superacid of this kind is fluoroantimonic acid. Another group of superacids, the carborane acid group, contains some of the strongest known acids. Finally, when treated with anhydrous acid, zeolites [ citation needed ] (microporous aluminosilicate minerals) will contain superacidic sites within their pores.
Strong bases are leveling solvents for acids, weak bases are differentiating solvents for acids. In a leveling solvent, many acids are completely dissociated and are thus of the same strength. All acids tend to become indistinguishable in strength when dissolved in strongly basic solvents owing to the greater affinity of strong bases for protons.
Carboxylic acids are organic acids characterized by a carboxyl (-COOH) functional group. The naming of these compounds is governed by IUPAC nomenclature, which ensures systematic and consistent naming of chemicals. Numerous organic compounds have other common names, often originating in historical source material thereof.
HSAB is an acronym for "hard and soft (Lewis) acids and bases".HSAB is widely used in chemistry for explaining the stability of compounds, reaction mechanisms and pathways. It assigns the terms 'hard' or 'soft', and 'acid' or 'base' to chemical species.
This equation reproduces and predicts the enthalpy, ΔH, of a reaction between many acids and bases. ΔH is a measure of strength of the bond between the acid and the base, both in the gas phase and in weakly solvating media. Entropy effects are ignored. A matrix presentation of the equation enhances its utility. [3]