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Carborane acids H(CXB 11 Y 5 Z 6) (X, Y, Z = H, Alk, F, Cl, Br, CF 3) are a class of superacids, [1] some of which are estimated to be at least one million times stronger than 100% pure sulfuric acid in terms of their Hammett acidity function values (H 0 ≤ –18) and possess computed pK a values well below –20, establishing them as some of the strongest known Brønsted acids.
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 (microporous aluminosilicate minerals) will contain superacidic sites within their pores.
A Lewis base is often a Brønsted–Lowry base as it can donate a pair of electrons to H +; [11] the proton is a Lewis acid as it can accept a pair of electrons. The conjugate base of a Brønsted–Lowry acid is also a Lewis base as loss of H + from the acid leaves those electrons which were used for the A—H bond as a lone pair on the ...
Specific and general catalysis is also found in base catalysed reactions and base Brønsted equation also exists with constant β. The Brønsted equation gives information about a reaction mechanism. Reactions that have low values for proportionality constants α or β are considered to have a transition state closely resembling the reactant ...
Likewise, any aqueous base with an association constant pK b less than about 0, corresponding to pK a greater than about 14, is leveled to OH − and is considered a strong base. [22] Nitric acid, with a pK value of around −1.7, behaves as a strong acid in aqueous solutions with a pH greater than 1. [23] At lower pH values it behaves as a ...
Its conjugate base is the acetate ion with K b = 10 −14 /K a = 5.7 x 10 −10 (from the relationship K a × K b = 10 −14), which certainly does not correspond to a strong base. The conjugate of a weak acid is often a weak base and vice versa.
Crystalline benzoic acid shown here is a solid and an acid, but, in the context of this article, it is not a "solid acid", which are polymeric materials and typically stronger acids.
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.