Bases hydrogen ions released

Practically, the result of reactions (48) and (49) is reaction (50). In reaction (50), we see that acetic acid acts as an acid in the same sense that it does in (48). In either case, it releases hydrogen ions. In (48) acetic acid releases hydrogen ions and forms H+(aq) and in (50) it releases hydrogen ions to NHs and forms NH/. In the same way, ammonia acts as a base in (50) by reacting with the hydrogen ion released by acetic acid. So reaction (50) is an acid-base reaction, though the net reaction does not show H+(aq) explicitly. 

Methods that attempt to measure the sulfonate content directly are based on retention of benzidinium ions by sulfonate groups (Sjostrom and Enstrom 1966), titration of the hydrogen ions released when a sulfite pulp in its acid form is washed with potassium chloride adjusted to pH 4 (Cappelen and Schoon... 

We see in Table 11-IV that the equilibrium view of acid strengths suggests that we regard water itself as a weak acid. It can release hydrogen ions and the extent to which it does so is indicated in its equilibrium constant, just as for the other acids. We shall see that this type of comparison, stimulated by our equilibrium considerations, leads us to a valuable generalization of the acid-base concept. 

These compounds are called Arrhenius acids and bases. For instance, HCI is an Arrhenius acid, because it releases a hydrogen ion, H+ (a proton), when it dissolves... 

Arrhenius thought something similar to disassociation happened to bases, too. But he believed that instead of releasing a positive hydrogen ion like acids do, bases contributed a hydroxide ion to the solution. A hydroxide ion is a negative ion, and it is written OH-. For example, if the base sodium hydroxide is dissolved in water, it will break up into sodium ions and hydroxide ions, as follows ... 

So, Arrhenius defined an acid as any substance that releases hydrogen ions (H+) when it is dissolved in water. He defined a base as any substance that releases hydroxide ions (OH"). This would explain why acids all have similar properties—because they all release H+ ions. It also explains the similarities among bases. All bases, according to Arrhenius definition, release OH" ions. It also explains why water forms when acids and bases are mixed . 

The Bronsted-Lowry definition of an acid is essentially the same as Arrhenius idea An acid is any substance that releases a hydrogen ion. Their idea has come to be known as the Bronsted-Lowry theory of acids and bases. 

In contrast to the flavin-dependent monoamine oxidases, SSAO/VAP-1 has evolved to hydroxylate a tyrosine residue in the active site which is further oxidized to the quinone state by oxygen in the presence of copper ion releasing hydrogen peroxide [28-30]. The primary amine in the substrate (R-NH2, Scheme 1) forms a Schiff-base with the quinone carbonyl group, which through a series of steps ultimately releases the aldehyde product. 

An acid/base theory stating (a) that an acid is any substance that tends to donate or release protons (also called hydrogen ions) to a base, and (b) that a base is a substance that accepts or removes protons from an acid. Examples of Brpnsted acids include H3O+, H2O, CH3COOH, and HS04 . Examples of Brpnsted bases include H2O, OH", CH3COO, and SO42. ... 

S. A. Arrhenius defined an acid as any hydrogen-containing species able to release protons and a base as any species able to form hydroxide ions [71]. The aqueous acid-base reaction is the reaction between hydrogen ions and hydroxide ions with water formation. The ions accompanying the hydrogen and hydroxide ions form a salt, so the overall Arrhenius acid-base reaction can be written ... 

Ions released into the matrix as the cement sets may interact with the organic part of the matrix. Metal ions, such as Ca + and AP+, may be chelated by car-boxylate groups, either on the polymer or on the tartaric acid additive. These have been considered in reasonable detail in the literature [230]. What has received far less attention is the possibility that fluoride ions might interact with carboxylic acid groups, either to modify the setting reaction or to become relatively securely anchored within the set cement. This possibility was raised in a review published in 1998 [230], but has not been followed up subsequently. It is based on the well-established observation that fluoride ion will form extremely strong hydrogen bonds with carboxylic acids in aqueous solution. They are of the type ... 

In the case of water, however, the concentration of either the OH- or H+ ions can be decreased by adding proton donors (acids) or proton acceptors (bases). Thus, a proton donor releases hydrogen ions into the solution (i.e., increases), and the only way the product Kw (i.e., COH-CH+) remains a constant is by a decrease in ( OH ... 

The greater the acidity of a solution, the lower its pH. Weak acids partially ionize to release a hydrogen ion, thus lowering the pH of the aqueous solution. Weak bases accept a hydrogen ion, increasing the pH. The extent of these processes is characteristic of each particular weak acid or base and is expressed as a disso-... 

We shall call such substances Arrhenius acids and bases. For instance, HC1 is an Arrhenius acid, because it releases a hydrogen ion, H+ (a proton), when it dissolves in water CH4 is not an Arrhenius acid, because it does not release hydrogen ions in water. Sodium hydroxide is an Arrhenius base because OH ions go into solution when it dissolves ... 

Why do we use the terms acid and base in this context Recall from Section J that acids and bases are normally discussed in terms of the behavior of a hydrogen ion, H+ (a proton), and that, in water, an acid such as HC1 donates its proton to a neighboring water molecule. We could imagine this reaction as taking place in two hypothetical steps first, an HC1 molecule releases a hydrogen ion as soon as it dissolves in water and then that hydrogen ion immediately bonds to a neighboring water molecule. The second step is... 

In addition to changing the pH of the water, the uptake and release of CO2 alter the buffer capacity of the water. The effect upon buffer capacity is the result of two factors (1) the dependence of buffer capacity on the hydrogen ion concentration, and (2) the dependence of buffer capacity on the total concentration of weak acid and conjugate base in solution (67, 68). The precipitation of CaCO in natural waters reduces the buffer capacity to a value lower than that predicted on the basis of pH change and respiratory or photosynthetic changes in COL content of the water. 

Such an equilibrium system is termed a conjugate (or corresponding) acid-base system. A and B are termed a conjugate acid-base pair. It is important to realize that the symbol H+ in this definition represents the bare proton (unsolvated hydrogen ion), and hence the new definition is in no way connected to any solvent. The equation expresses a hypothetical scheme for defining the acid and base - it can be regarded as a half reaction which takes place only if the proton, released by the acid, is taken up by another base. 

FIGURE 13. Species identified in the reaction cycle of copper amine oxidases. Oxidised, resting state enzyme (1) reacts with substrate to form a substrate Schiff base (2). Proton abstraction by the active site base (Asp383 in ECAO) leads, via a carbanion intermediate (3) to the product Schiff base (4). Hydrolysis releases the product aldehyde, leaving reduced cofactor in equilibrium between aminoquinol/Cu (S) and semiquinone/Cu (6). The reduced cofactor is reoxidised by molecular oxygen, releasing ammonium ions and hydrogen peroxide. (Modified from Wilmot et al., 1999 with permission). 

Sverdrup et al. (1992) have developed the PROFILE model, which is based on the principle of continuity of alkalinity or ANC in soil. The critical load is defined as the allowable acid loading that will not acidify forest soils and cause the release of aluminum and hydrogen ions to soil solution ... 

We notice that the carbonium ion combines with water to form not the alcohol but the protonated alcohol in a subsequent reaction this protonated alcohol releases a hydrogen ion to another base to form the alcohol. This sequence of reactions, we can see, is just the reverse of that proposed for the dehydration of alcohols (Sec. 5.20). In dehydration, the equilibria are shifted in favor of the alkene chiefly by the removal of the alkene from the reaction mixture by distillation in hydration, the equilibria are shifted in favor of the alcohol partly by the high concentration of water. 

A halide ion is an extremely weak base. Its reluctance to share its electrons is shown by its great tendency to release a hydrogen ion, that is, by the high acidity of the hydrogen halides. 

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