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Pauling's second rule is that the value of the first pK a for acids of the formula XO m (OH) n depends primarily on the number of oxo groups m, and is approximately independent of the number of hydroxy groups n, and also of the central atom X. Approximate values of pK a are 8 for m = 0, 2 for m = 1, −3 for m = 2 and < −10 for m = 3. [28]
The Henderson–Hasselbalch equation can be used to estimate the pH of a buffer solution by approximating the actual concentration ratio as the ratio of the analytical concentrations of the acid and of a salt, MA. The equation can also be applied to bases by specifying the protonated form of the base as the acid.
The PBE is a modification of Poisson's equation that incorporates a description of the effect of solvent ions on the electrostatic field around a molecule. The H++ web server , [ 7 ] the pKD webserver , [ 8 ] MCCE2 , Karlsberg+ , [ dead link ] PETIT and GMCT use the FDPB method to compute p K a values of amino acid side chains.
In chemistry, biochemistry, and pharmacology, a dissociation constant (K D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a complex falls apart into its component molecules, or when a salt splits up into its component ions.
Acid strength is the tendency of an acid, symbolised by the chemical formula, to dissociate into a proton, +, and an anion, .The dissociation or ionization of a strong acid in solution is effectively complete, except in its most concentrated solutions.
The pKa of KHP is 5.4, so its pH buffering range would be 4.4 to 6.4; however, due to the presence of the second acidic group that bears the potassium ion, the first pKa also contributes to the buffering range well below pH 4.0, which is why KHP is a good choice for use as a reference standard for pH 4.00. [8] [9]
Potassium hydrogen diacetate (CAS #4251-29-0) with formula KH(OOCCH 3) 2 is a related food additive with the same E number as potassium acetate. Medicine and biochemistry
The formula for this acid is generally written H 3 PO 2, but a more descriptive presentation is HOP(O)H 2, which highlights its monoprotic character. Salts derived from this acid are called hypophosphites. [3] HOP(O)H 2 exists in equilibrium with the minor tautomer HP(OH) 2. Sometimes the minor tautomer is called hypophosphorous acid and the ...