Acid-base chemistry Bronsted-Lowry theory

For aqueous solutions, the Bronsted-Lowry theory adequately describes the behavior of acids and bases. We shall limit our discussion of acid-base chemistry to aqueous solutions and use the following definitions ... 

The Bronsted-Lowry theory contributed several fundamental ideas that broadened our understanding of solution chemistry. First of all, an acid-base reaction is a charge-transfer process. Second, the transfer process usually involves the solvent. Water may, in fact, accept or donate a proton. Last, and perhaps most important, the acid-base reaction is seen as a reversible process. This leads to the possibility of a reversible, d)mamic equilibrium (see Section 8.4). 

The acid-base concept, either in the limited interpretation of the Bronsted-Lowry theory or in the more general sense of the Lewis theory, is one of the most useful classification schemes in chemistry and a tool for systematizing the relationship between structure and reactivity. In this section we examine how this general concept can be applied to solid surfaces [29], From the most general (Lewis) point of view, a surface is classified as acidic (electron acceptor) or basic (electron donor) according to the direction of net electron transfer that results in the formation of new chemical bonds with an adsorbed molecule. 

The Lewis theory, by virtue of its broader definition of acids, allows acid—base theory to include all of the Bronsted-Lowry reactions and, as we shall see, a great many others. Most of the reactions we shall study in organic chemistry involve Lewis acid—base interactions, and a sound understanding of Lewis acid—base chemistry will help greatly. 

Feb. 22,1879, Varde, Denmark - Dec. 17,1947, Copenhagen, Denmark) Ph.D. Copenhagen 1908, since 1908 Professor of Chemistry (the 3rd chair, i.e., the chair of Physical Chemistry at the Univ. of Copenhagen). 1926/27 visiting Professor at Yale Univ., New Haven, Connecticut, USA. Famous for his work on chemical reaction kinetics, chemical affinity, indicators, and thermodynamics of solutions. He could explain the effect of activity coefficients on reaction rates in solutions. In 1923 he developed independently of - Lowry, and - Bjerrum a new -> acid-base theory, the so-called Bronsted acid-base theory. 

The addition of acid to the solution leads to shifts in the equilibria that favor the aqua-form of the complex. Thus, Pfeiffer, in 1906, established the reversible transformation of aqua-complexes into hydroxo-complexes. Werner later used this observation in the development of add-base concepts in coordination chemistry.32 Werner s work in this field is now largely of historical interest but two points, emphasized by Werner, remain espedally noteworthy, i.e. the importance of solvent in add-base equilibria and that bases may be considered as proton acceptors. These statements were incorporated into the acid-base theory developed by Bronsted and Lowry in 1923. 

Ideas about adds and bases (or alkalis) date back to ancient times. The word acid is derived from the Latin acidus (sour). Alkali (base) comes from the Arabic al-qali, referring to the ashes of certain plants from which alkaline substances can be extracted. The acid-base concept is a major theme in the history of chemistry. In this section, we emphasize the view proposed by Svante Arrhenius in 1884 but also introduce a more modern theory proposed in 1923 by Thomas Lowry and by Johannes Bronsted. 

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