autoprotolysis

autoprotolysis

[‚ȯd·ō·prə′täl·ə·səs]
(chemistry)
Transfer of a proton from one molecule to another of the same substance.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
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The dissociation of water molecules in the liquid water or autoprotolysis extending the scheme 2[H.sub.2]O [right arrow] [OH.sup.-] + O[H.sub.3.sup.+] leads to the presence of some equilibrium level of hydroxyl ions and hydronium ions.
However, the microwaves could give further influence on the reaction of autoprotolysis by the reorienting of the interacting polar molecules and a corresponding change in the activation energy.
Bosch, "Autoprotolysis in aqueous organic solvent mixtures," Analytical Chemistry, vol.
Aslan, "Determination of autoprotolysis constants of water-organic solvent mixtures by potentiometry," Microchimica Acta, vol.
As far as autoprotolysis constant (N,N- dimethyl formamide (pKs = 18.0) Greater than acetonitrile (pKs = 33.0) Greater than isopropyl alcohol (pKs = 20.6) Greater than t-butyl alcohol (pKs = 22.0)), all compounds show the weakest acidic properties in N,N-dimethyl formamide, isopropyl alcohol and t-butyl alcohol but show the strongest acidic properties in acetonitrile.
Autoprotolysis is an acid-base reaction between identical solvent molecules is which some act as an acid and others as a base.
[H.sub.2]O is amphiprotic solvent, where autoprotolysis is observable.
The autoprotolysis constant of AN is very low: [pK.sub.auto] [greater than or equal to] 33 [22] (even values of [pK.sub.auto] as high as 44 have been suggested [16, 23]), which makes it a good differentiating solvent.
Although water and alcohol are both amphiprotonic solvents, the autoprotolysis occurs to a higher extent in water than in tert-butanol.
Sulfuric acid undergoes self-ionization or autoprotolysis in the same manner as water and many other protonic solvents [4]: [Mathematical Expression Omitted] Just as the acidity of an aqueous solution is increased by increasing the concentration of [H.sub.3.O.sup.+], the acidity of [H.sub.2.SO.sub.4] can be further increased by a solute HA that behaves as an acid, thereby increasing the concentration of the [H.sub.3.SO.sup.+.sub.4] ion: [Mathematical Expression Omitted] There are only a few acids that are strong enough to ionize in this way.
The steep rise in acidity in the region of the pure solvent is a consequence of the very small autoprotolysis constant which is comparable to that of water.