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The E and C parameters refer, respectively, to the electrostatic and covalent contributions to the strength of the bonds that the acid and base will form. The equation is -ΔH = E A E B + C A C B + W. The W term represents a constant energy contribution for acid–base reaction such as the cleavage of a dimeric acid or base.
In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base.It can be used to determine pH via titration.Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
The Brønsted–Lowry theory (also called proton theory of acids and bases [1]) is an acid–base reaction theory which was first developed by Johannes Nicolaus Brønsted and Thomas Martin Lowry independently in 1923.
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.
This is called general acid and general base theory. The easiest way to distinguish between them is to check whether the reaction rate is determined by the concentrations of the general acid and base. If the answer is yes then the reaction is the general type. Since most enzymes have an optimum pH of 6 to 7, the amino acids in the side chain ...
When a strong acid is dissolved in water, it reacts with it to form hydronium ion (H 3 O +). [2] An example of this would be the following reaction, where "HA" is the strong acid: HA + H 2 O → A − + H 3 O + Any acid that is stronger than H 3 O + reacts with H 2 O to form H 3 O +. Therefore, no acid stronger than H 3 O + exists in H 2 O.
A Lewis base is also a Brønsted–Lowry base, but a Lewis acid does not need to be a Brønsted–Lowry acid. The classification into hard and soft acids and bases ( HSAB theory ) followed in 1963. The strength of Lewis acid-base interactions, as measured by the standard enthalpy of formation of an adduct can be predicted by the Drago–Wayland ...
The triad of cytomegalovirus protease [b] uses histidine as both the acid and base triad members. Removing the acid histidine results in only a 10-fold activity loss (compared to >10,000-fold when aspartate is removed from chymotrypsin). This triad has been interpreted as a possible way of generating a less active enzyme to control cleavage ...