Bronsted-Lowery acid

Along with the Bronsted-Lowery concept of a proton donor (acid) and a proton acceptor (base), arises the concept of conjugate acid-base pairs. For... 

The two clear, colorless gases mix, and a white solid of ammonium chloride forms. I show the intermediate formation of the ions in the equation so that you can better see what s actually happening. The HCl transfers an H to the ammonia. That s basically the same thing that happens in the HCl/NaOH reaction, but the reaction involving the ammonia can t be classified as an acid-base reaction, because it doesn t occur in water, and it doesn t involve the hydroxide ion. But again, the same basic process is taking place in both cases. In order to account for these similarities, a new acid-base theory was developed, the Bronsted-Lowery theory. 

The Bronsted-Lowery theory attempts to overcome the limitations of the Arrhenius theory by defining an acid as a proton (H ) donor and a base as a proton (Tl ) acceptor. The base accepts the H by furnishing a lone pair of electrons for a coordinate-covalent bond, which is a covalent bond (shared pair of electrons) in which one atom furnishes both of the electrons for the bond. Normally, one atom furnishes one electron for the bond and the other atom furnishes the second electron (see Chapter 7). In the coordinate-covalent bond, one atom furnishes both bonding electrons. 

I discuss acid-base reactions under the Bronsted-Lowery theory in the section Give me that proton Bronsted-Lowery acid-base reactions, later in this chapter. 

With the Arrhenius theory, acid-base reactions are neutralization reactions. With the Bronsted-Lowery theory, acid-base reactions are a competition for a proton. For example, take a look at the reaction of ammonia with water ... 

The mixtures of weak acids and bases may be conjugate acid-base pairs (such as H2CO3/HCO3 ) or nonconjugate acid-base pairs (such as NH4+/CH3COO ). (For more info about conjugate acid-base pairs, see Give me that proton Bronsted-Lowery acid-base reactions, earlier in this chapter.)... 

Buffer b9-f9r often attributive [buff v., to react like a soft body when struck] (1835) n. A solution which contains moderate or high concentrations of a Bronsted-Lowery conjugate acid-base pair a solution whose pH does not change greatly in response to added acids or bases. 

Bronsted and Lowery said that an acid reacts with a base to form conjugate acid-base pairs. Conjugate acid base pairs differ by a single H+. NH3 is a base, for example, and NH4 is its conjugate acid. H2O is an acid in the reaction between ammonia and water, and OH is its conjugate base. In this reaction, the hydroxide ion is a strong base and ammonia is a weak base, so the equilibrium is shifted to the left — there s not much hydroxide at equilibrium. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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