Acids molecular definitions

The preconditions of another approach to the treatment of acid-base concepts can be found in the classic solvosystem concept described above. Careful reading of this concept shows that the acid-base definition connects the terms acid and base only with the process of autodissociation of a molecular solvent or of one capable of ionization. Nevertheless, it is obvious that acid-base interactions can occur in those solvents, which are not able to form acid and base owing to a dissociation process. Aprotic solvents may serve as a typical example of solvents of such a kind another case of solvents incapable of the acid-base autodissociation takes place if we consider the Lux acid-base equilibria in molten oxygen-free media. Therefore, in relation to any given acid or base there exist two kinds of solvents of differing auto-dissociation ability with the formation of the said acid or base [36, 37, 44, 45]. 

The final acid-base concept we consider was developed by Gilbert N. Lewis, whose contribution to understanding the importance of valence electron pairs in molecular bonding we discussed in Chapter 9. Whereas the Brpnsted-Lowry concept focuses on the proton in defining a species as an acid or a base, the Lewis concept highlights the role of the electron pair. The Lewis acid-base definition holds that... 

Molecular Orbital (MO) approach to acid-base reactions Translated into the idiom of molecular orbital theory, the acid-base definitions should be read as follows ... 

The Lewis definition is perhaps the most widely used acid-base definition because it is applicable to both inorganic and organic molecules. Table 14.5 summarizes some of the different types of molecular species that exhibit Lewis acid-base behavior. 

Rupasinghe SG, Duan H, Schuler MA (2007) Molecular definitions of fatty acid hydroxylases in Arabidopsis thaliana. Proteins 68 279-293... 

Molecular Definitions of Acids 14.8 Water Acid and Base in Combustion 514... 

In the 1880s, the Swedish chemist Svante Arrhenius proposed the following molecular definitions of acids and bases. 

The earliest definition that highlighted the molecular nature of acids and bases is the Arrhenius acid-base definition, which classifies these substances in terms of their... 

Acids are described by their properties (sour taste, ability to dissolve metals, ability to neutralize bases, ability to turn litmus red) (13.1, 13.2) or by their molecular definitions (H+ producer, proton donor) (13.4). Bases are described by their properties (bitter taste, slippery feel, ability to neutralize acids, ability to turn litmus blue) (13.3) or by their molecular definition (0H producer, proton acceptor) (13.4). Acids and bases are either strong (complete dissociation in water) or weak (partial dissociation in water) (13.5). The acidity or basicity of a solution is specified using the pH scale in which pH = 7 specifies a neutral solution pH > 7, a basic solution and pH < 7, an acidic solution (13.6-13.8). 

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