Acid-base definitions

When developed, this theory proved to be more general than the theory of Lewis, for it includes all the above acid-base definitions and also includes oxidation-reduction reactions. 

The various acid-base definitions are summarized in the Venn diagram (Fig. 2.1). From this it can be seen that the Usanovich definition subsumes the Lewis definition, which in turn subsumes all other definitions (i.e. Arrhenius, Bronsted-Lowry, Germann-Cady-Elsey, Lux-Flood). 

Jensen, W. B. (1978). The Lewis acid-base definitions a status report. Chemical Reviews, 78, 1-22. 

In silicate melts and other nonprotonated solvents, the Bronsted-Lowry equation is not applicable and is conveniently replaced by the Lux-Flood acid-base definition (Lux, 1939 Flood and Forland, 1947), according to which free oxygen 0 replaces A basic oxide is one capable of furnishing oxygen ions, and an acidic oxide is one that associates oxygen ions ... 

Although many other acid-base definitions have been proposed and have been useful in particular types of reactions, only a few have been widely adopted for general use. Among them are those attributed to Arrhenius (based on hydrogen and hydroxide ion formation), Br0nsted-Lowry (hydrogen ion donors and acceptors), and Lewis (electron pair donors and acceptors) [6,67-70]. 

An example of the different points of view and different tastes in the matter of acid-base definitions was provided to one of the authors in graduate school while attending lectures on acid-base chemistry from two professors. One Felt that the solvent system was very useful, but that the Lewis concept went too far because it included coordination chemistry. The second used Lewis concepts in all of his work, but felt uncomfortable with the Usanovich definition because it included redox chemistry To the latter s credit, however, he realized that the separation was an artificial one, and he suggested the pyridine oxide example given above. 

Antiferromagnetism, 467-468 Aprotic solvents, 369-373 Aqueous solvents, and non-aqueous solvents. 359-386 Arachno structures, 798-800, 807 Aragonite, 98, 953 Arene complexes, 681-683 Arrhenius acid-base definition, 319... 

Arrhenius definitions are the earliest and the most simplistic of acid-base definitions. Of the three definitions, arrhenius definitions are the least inclusive, but the most commonly known acids and bases can be defined by Arrhenius. 

The Lewis acid-base definitions include reactions having nothing to do with protons. Following are some examples of Lewis acid-base reactions. Notice that the common Br0nsted-Lowry acids and bases also fall under the Lewis definition, with a proton serving as the electrophile. Curved arrows (red) are used to show the movement of electrons, generally from the nucleophile to the electrophile. 

Metal carbonyl complexes are an interesting series of coordination compounds in which the ligands are CO molecules, and in many cases the metals are present in a zero oxidation state. In these complexes, both the metal and ligand are soft according to the Lewis acid-base definitions. Although the discussion at first will be limited to the binary compounds containing only metal and CO, many mixed complexes are known that contain both CO and other ligands. 

For each of the following reactions identify the acid and the base. Also indicate which acid-base definition (Lewis, solvent system, Brpnsted) applies. In some cases, more than one definition may apply. 

---