Neutralization reactions Arrhenius concept

Note that HA and B are not necessarily neutral. They could be ions that are capable of acting as an acid or a base. This is one of the features of the Bronsted-Lowry concept that broadens the definitions of acids and bases over the Arrhenius concept—there are many more substances that can behave as acids or bases. Further, we can write the reaction including the solvent, water in this case, and the associated Ka. 

Arrhenius acid-base theory - Arrhenius developed the theory of the electrolytic dissociation (1883-1887). According to him, an acid is a substance which delivers hydrogen ions to the solution. A base is a substance which delivers hydroxide ions to the solution. Accordingly, the neutralization reaction of an acid with a base is the formation of water and a salt. It is a so-called symmetrical definition because both, acids and bases must fulfill a constitutional criterion (presence of hydrogen or hydroxide) and a functional criterion (to deliver hydrogen ions or hydroxide ions). The theory could explain all of the known acids at that time and most of the bases, however, it could not explain the alkaline properties of substances like ammonia and it did not include the role of the solvent. -> Sorensen (1909) introduced the -> pH concept. 

The solvent concept for nonaqueous solvents works exactly like the Arrhenius theory does for aqueous solutions. Autoionization and typical neutralization reactions can be shown as follows for several solvents. For liquid S02,... 

Arrhenius concept, 534, 535, 536 Bronsted-Lowry concept, 536, 536 537-538, 537f, 558 examples of, 533 533f neutralization reactions of, 548-549, 548f, 549f, 550... 

Acid-base reactions Within the Arrhenius concept, neutralization of H+ by OH is the only type of acid-base reaction that can occur. The Brpnsted concept broadens our view, encompassing a wide variety of reactions whose common feature is the transfer of a proton from a donor to an acceptor (Table 2). 

The classical properties of adds and bases are listed in the introduction to the chapter. As an example of how a property relates to the ion associated with it, an acid-base neutralization is H+ + OH —> HjO. 3. An Arrhenius base is a source of OH ions, whereas a Br0nsted-Lowry base is a proton remover. The two are in agreement, as the OH ion is an excellent proton remover. Other substances, howeva-, can also remove protons, so there are other bases according to the Br0nsted-Lowry concept. 5. In the reaction shown below, AICI3, a Lewis add, accepts an electron pair from Q , a Lewis base, in a Lewis add—Lewis base neutralization reaction. 

According to the Arrhenius theory of acids and bases, the acidic species in water is the solvated proton (which we write as H30+). This shows that the acidic species is the cation characteristic of the solvent. In water, the basic species is the anion characteristic of the solvent, OH-. By extending the Arrhenius definitions of acid and base to liquid ammonia, it becomes apparent from Eq. (10.3) that the acidic species is NH4+ and the basic species is Nl I,. It is apparent that any substance that leads to an increase in the concentration of NH4+ is an acid in liquid ammonia. A substance that leads to an increase in concentration of NH2- is a base in liquid ammonia. For other solvents, autoionization (if it occurs) leads to different ions, but in each case presumed ionization leads to a cation and an anion. Generalization of the nature of the acidic and basic species leads to the idea that in a solvent, the cation characteristic of the solvent is the acidic species and the anion characteristic of the solvent is the basic species. This is known as the solvent concept. Neutralization can be considered as the reaction of the cation and anion from the solvent. For example, the cation and anion react to produce unionized solvent ... 

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