Proton Br0nsted-Lowry theory

Acids and bases are defined in accordance with Br0nsted-Lowry theory in terms of their propensity to donate or accept hydrated protons in aqueous... 

Identify each of the following terms (a) hydronium ion, (b) Br0nsted-Lowry theory, (c) proton (Brpnsted sense), (d) acid (Brpnsted sense), (e) base (Brpnsted sense), (f) conjugate, (g) strong acid or base, Qi) acid dissociation constant, i) base dissociation constant, (/) autoionization, k) pH, and (Z) K. ... 

Br0nsted-Lowry theory a theory of acids and bases that defines acids as proton donors and bases as proton acceptors. 

In contrast to the Br0nsted-Lowry theory, which emphasizes the proton as the principal species in acid-ba.se reactions, the definition proposed by Lux and extended by Floods describes acid-base behavior in terms of the oxide ion. This acid-base concept was advanced to treat nonprotonic systems which were not amenable to the Br0nsted-Lowry definition. For example, in high-temperature inorganic melts, reactions such as the following take place ... 

Lux—Flood Definition In contrast to the Br0nsted-Lowry theory, which emphasizes the proton as the... 

The Br0nsted-Lowry theory assumes a transfer of protons from an acid to a base, i.e., conjugate pairs. 

BR0NSTED-LOWRY THEORY—TAKING AND GIVING PROTONS... 

In Chapter 5 we saw that, in terms of the Br0nsted-Lowry theory, acid-base reactions involve proton transfer. Another large and important group of chemical reactions, particularly in aqueous solutions, involves electron transfer these are referred to as oxidation-reduction (or redox) reactions. Redox reactions are involved (1) in photosynthesis, which releases oxygen into the Earth s atmosphere (2) in the combustion of fuels, which is responsible for rising concentrations of atmospheric carbon dioxide (3) in the formation of acid precipitation and (4) in many chemical reactions in Earth sediments. 

The Br0nsted-Lowry theory of acids and bases involves the transfer of protons or hydrogen ions within an aqueous solution. An acid is defined as a molecule or ion that acts as a proton donor and a base is defined as a molecule or ion that acts as a proton acceptor. For example, when hydrogen chloride gas is dissolved in water it reacts to form hydrochloric acid. The following equilibrium is established ... 

The shortcomings of the Arrhenius theory led chemists to seek other explanations for the nature of acids and bases. The Br0nsted-Lowry theory was introduced independently in 1923 by the Danish chemist Johannes Nicolaus Brqnsted and the English chemist Thomas Martin Lowry, stating that any compound that can transfer a proton to any other compound is an acid, and the compound that accepts the proton is a base. Their theory explained the behaviour of all of the acids and bases covered by the Arrhenius theory, but also was able to resolve some of the problems with that theory. That is, they were able to explain why some salts are acidic and basic (due to salt hydrolysis) and why no free protons are found in the solutions of some acids. 

Our principal interest in acid-base chemistry is in aqueous solutions, where the Br0nsted-Lowry theory prevails. The balance of this chapter is limited to the proton-transfer concept of acids and bases. 

Bases are much the same in the Lewis theory and in the Brpnsted-Lowry theory, because in the Br0nsted-Lowry theory a base must donate a pair of electrons in order to accept a proton. 

Br0nsted-Lowry theory of acids and bases (Section 3.2A) An acid is a substance that can donate (or lose) a proton a base is a substance that can accept (or remove) a proton. The conjugate acid of a base is the molecule or ion that forms when a base accepts a proton. The conjugate base of an acid is the molecule or ion that forms when an acid loses its proton. 

This equation recognizes the solvent by including a solvent molecule on the left-hand side. What happens is that a proton, H+, is transferred from HCl to H2O (Figure 3.1). This transfer of protons is the basis of the Br0nsted-Lowry theory ... 

According to the Br0nsted-Lowry theory, the key feature of the dissolution of HCl in water is the transfer of a proton from a molecule of HCl to a water molecule. 

The Br0nsted-Lowry theory is stated in terms of proton transfer, rather than through ions in aqueous solution, and so it can be applied in non-aqueous systems. Thus, if gaseous ammonia and hydrogen chloride are mixed, a white smoke consisting of the ionic salt, ammonium chloride, is formed... 

On the Br0nsted-Lowry theory, the Arrhenius H+/OH neutralization reaction involves proton transfer from H3O+ to OH , with the production of two water molecules. 

According to the Br0nsted-Lowry theory, an acid is a substance from which a proton can be removed a base is a substance that can accept a proton from an acid. 

The Arrhenius definition of an acid and a base attributed acidity to the presence of H" (aq), and alkalinity to OH (aq). Br0nsted-Lowry theory generalizes the acid-base concept by focusing on proton transfer, rather than on particular aqueous ions. Here, we discuss an attempt to generalize it further by focusing on the changes in electronic structure that occur when acid-base reactions take place, ideas introduced by G. N. Lewis. 

The limitations of the Arrhenius theory of acids and bases are overcome by a more general theory, called the Bronsted-Lowry theory. This theory was proposed independently, in 1923, by Johannes Br0nsted, a Danish chemist, and Thomas Lowry, an English chemist. It recognizes an acid-base reaction as a chemical equilibrium, having both a forward reaction and a reverse reaction that involve the transfer of a proton. The Bronsted-Lowry theory defines acids and bases as follows ... 

A more general theory of acids and bases was devised independently by Johannes Br0n-sted (Denmark) and Thomas M. Lowry (England) in 1923. In the Br0nsted-Lowry approach, an acid is a proton donor, and a base is a proton acceptor. The reaction that occurs between an acid and a base is proton transfer. 

The theory of solvent systems is suitable for ionizable solvents, but it is not ap-phcable to acid-base reactions in nonionizable solvents such as benzene or diox-ane. In 1923, Br0nsted and Lowry separately described what is now known as the Br0nsted-Lowrv theory. This theory states that an acid is any substance that can donate.a proton, and a base is any substance that can accept a proton. Thus, we can write a half-reaction ... 

Brnnsted-Lowry theory The description of an acid as a proton donor and a base as a proton acceptor also known as the Br0nsted theory. 

The Arrhenius concept was the first successful theory of acids and bases. Then in 1923, Br0nsted and Lowry characterized acid-base reactions as proton-transfer reactions. According to the Br0nsted—Lowry concept, an acid is a proton donor and a base is a proton acceptor. The Lewis concept is even more general than the Br0nsted-Lowry concept. A Lewis acid is an electron-pair acceptor and a Lewis base is an electron-pair donor. Reactions of acidic and basic oxides and the formation of complex ions, as well as proton-transfer reactions, can be described in terms of the Lewis concept. 

The Br0nsted-Lowry definition of acids and bases broadened the definition of acids and bases. Acids are proton donors and bases are proton acceptors. This is in agreement with Arrhenius theory but includes reactions such as that between ammonia and hydrogen chloride gases ... 

Br0nsted-Lowry acid-base theory, proton-transfer reaction, proton source, proton remover, amphoteric... 

Equilibria involving acids and bases are discussed from within the Lowry-Br0nsted theory, which defines an acid as a proton donor and a base as a proton acceptor (or abstracter ). The additional concept of pH is then introduced. Strong and weak acids are discussed in terms of the acidity constant Ka, and then conjugate acids and bases are identified. 

In his oxonium theory of acids and bases (91), Werner anticipated by 16 years the now generally accepted views of Br0nsted (7, 8) and Lowry (40j 41) y which accords that acids are proton donors and bases are proton acceptors. Yet, despite the fact that Werner was the first to emphasize the critical role of the solvent in acid-base phenomena, his contributions to this field are almost universally ignored. 

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