Bronsted-Lowry acid A proton donor

A nuclear reactor that produces more fissionable nuclear fuel than it consumes. Bronsted-Lowry Acid A proton donor. 

The sec-butyl cation can react as both a Bronsted-Lowry acid (a proton donor) and a Lewis acid (an electron pair acceptor) in the presence of a water-sulfuric acid mixture. In each case, however, the product is different. The two reactions are as follows ... 

T, F A conjugate base is formed from an acid that loses a proton. Bronsted-Lowry acids are proton donors and not acceptors. 

Lowry is best known to chemistry students through the tradition of eponymony, since the proton theory of acidity is known as the "Bronsted/Lowry theory" of proton donors. His most important experimental investigation likely was a long series of studies on optical rotatory dispersion.49 For our purposes, there is special interest in his discovery of mutarotation in camphor derivatives and his theory of dynamic tautomerism, which led him to an ionic theory of organic reaction mechanisms. 

Bronsted-Lowry acid A species that acts as a proton donor. 

Bronsted-Lowry acid A substance (molecule or ion) that acts as a proton donor. (Section 16.2)... 

The transfer of a proton always involves both an acid (donor) and a base (acceptor). In other words, a substance can function as an acid only if another substance simultaneously behaves as a base. To be a Bronsted-Lowry acid, a molecule or ion must have a hydrogen atom it can lose as an H ion. To be a Bronsted-Lowry base, a molecule or ion must have a nonbonding pair of electrons it can use to bind the H ion. 

Every base that we have discussed thus far—whether OH , H2O, an amine, or an anion—is an electron-pair donor. Everything that is a base in the Bronsted-Lowry sense (a proton acceptor) is also a base in the Lewis sense (an electron-pair donor). In the Lewis theory, however, a base can donate its electron pair to something other than H. The Lewis definition therefore greatly increases the number of species that can be considered acids in other words, is a Lewis acid but not the only one. For example, the reaction between NH3 and BF3 occurs because BF3 has a vacant orbital in its valence shell, ooo (Section 8.7) It therefore acts as an electron-pair acceptor (a Lewis acid) toward NH3, which donates the electron pair ... 

A useful definition of acids and bases is that independently introduced by Johannes Bronsted (1879-1947) and Thomas Lowry (1874-1936) in 1923. In the Bronsted-Lowry definition, acids are proton donors, and bases are proton acceptors. Note that these definitions are interrelated. Defining a base as a proton acceptor means an acid must be available to provide the proton. For example, in reaction 6.7 acetic acid, CH3COOH, donates a proton to ammonia, NH3, which serves as the base. 

According to the Bronsted-Lowry definition of acids and bases, an acid is a proton donor. The particle that is left over after an acid donates its proton, however, can now accept a proton and,... 

J. N. Bronsted and T. M. Lowry independently arrived at definitions of an acid and a base that do not involve water. They recognized that the essential characteristic of an acid-base reaction was the transfer of a hydrogen ion (proton) from one species (the acid) to another (the base). According to these definitions, an acid is a proton donor and a base is a proton acceptor. The proton must be donated to some other species so there is no acid without a base. According to Arrhenius, HC1 is an acid because... 

The Lowry-Bronsted theory says an acid is a proton donor. 

The concepts of the Lowry-Bronsted theory may explain the various reactions that take place during many non-aqueous titrations. Thus, an acid is a proton donor and a base is a proton acceptor. Therefore, when an acid HA undergoes dissociation it gives rise to a proton and the conjugate base A of the acid ... 

In 1923, Bronsted and Lowry defined an acid as a proton donor and a base as a proton acceptor. 

Under the Bronsted-Lowry definition, an acid is a substance that donates a hydrogen ion (H+) in an acid-base reaction, while a base is a substance that accepts that hydrogen ion from the acid. When ionized to form a hydrogen cation, hydrogen loses its one and only electron and is left with only a single proton. For this reason, Bronsted-Lowry acids are often called proton donors, and Bronsted-Lowry bases are called proton acceptors. 

The Arrhenius theory accounts for the properties of many common acids and bases, but it has important limitations. For one thing, the Arrhenius theory is restricted to aqueous solutions for another, it doesn t account for the basicity of substances like ammonia (NH3) that don t contain OH groups. In 1923, a more general theory of acids and bases was proposed independently by the Danish chemist Johannes Bronsted and the English chemist Thomas Lowry. According to the Bronsted-Lowry theory, an acid is any substance (molecule or ion) that can transfer a proton (H + ion) to another substance, and a base is any substance that can accept a proton. In short, acids are proton donors, bases are proton acceptors, and acid-base reactions are proton-transfer reactions ... 

In the reverse reaction, H30+ acts as the proton donor (acid) and A- acts as the proton acceptor (base). Typical examples of Bronsted-Lowry acids include not only electrically neutral molecules, such as HC1, HN03, and HF, but also cations and anions of salts that contain transferable protons, such as NH4+, HS04 , and HC03-. 

To account for the acidity of a substance, consider how it can produce H + ions in water (Arrhenius theory) and how it can act as a proton donor (Bronsted-Lowry theory). 

Nitrous acid is a Bronsted-Lowry acid because it acts as a proton donor when it dissociates, transferring a proton to water to give the hydronium ion ... 

According to the Arrhenius theory, acids (HA) are substances that dissociate in water to produce H + (aq). Bases (MOH) are substances that dissociate to yield OH aq). The more general Bransted-Lowry theory defines an acid as a proton donor, a base as a proton acceptor, and an acid-base reaction as a proton-transfer reaction. Examples of Bronsted-Lowry acids are HC1, NH4+, and HSO4- examples of Bronsted-Lowry bases are OH-, F-, and NH3. 

A point of this reaction is the release of H+ ions—the Bronsted-Lowry approach considers this the appearance of a proton from the acid. A Bronsted-Lowry acid is a proton donor. Note that the hydrogen ion is a proton, hydrogen s nucleus without the electron found in the atom. Then, a Bronsted-Lowry acid must contain a hydrogen. Of course, if the solvent were not to be water, this statement may not work because the cation released could be other than the hydrogen ion, but there might be other ions performing the same service (liquid ammonia autoionizes, Problem 17.3). 

There are several definitions of acids and bases. According to the Bronsted-Lowrv definition, an acid is a proton donor and a base is a proton acceptor. Any compound that has a hydrogen can potentially act as a Bronsted-Lowry acid (although the strength of the acid can vary enormously). Therefore, H—A is used as a general representation for an acid. To accept a proton, most bases... 

Bronsted-Lowry acid (Section 4.1) A proton donor. 

One very important thing to remember is that an acid and base are always present in these reactions. In order for a molecule or ion to donate a proton, there has to be another ion or molecule to receive it. In addition, in reversible acid-base reactions, the roles of the substances as proton donor or acceptor will switch in the reverse reaction. In the example below, note how water (a Bronsted-Lowry base in this reaction) accepts a proton to form a hydronium ion in the forward reaction. In the reverse reaction, the hydronium ion (Bronsted-Lowry acid) donates a proton and, after losing the proton, becomes the water molecule once again ... 

Bronsted acid-base theory — In 1923, Bron-sted and, independently of him, Lowry published essentially the same theory of acids and bases which can be applied not only to water as a solvent but also to all other - protic solvents, as well as to proton transfer reactions in gases. An acid is defined as a proton donor, i.e.,... 

In many chemistry references, Bronsted-Lowry acids are called "proton donors." Bronsted-Lowry bases are called "proton acceptors." Although these terms are common, they create a false impression about the energy that is involved in acid-base reactions. Breaking bonds always requires energy. For example, removing a proton from a hydrochloric acid molecule requires 1.4 x 103 kJ/mol. This is far more energy than the word donor" implies. 

The first person to recognize the essential nature of acids and bases was Svante Arrhenius. Based on his experiments with electrolytes, Arrhenius postulated that acids produce hydrogen ions in aqueous solution, and bases produce hydroxide ions. At the time of its discovery the Arrhenius concept of acids and bases was a major step forward in quantifying acid—base chemistry, but this concept is limited because it applies only to aqueous solutions and allows for only one kind of base—the hydroxide ion. A more general definition of acids and bases was suggested independently by the Danish chemist Johannes N. Bronsted (1879-1947) and the English chemist Thomas M. Lowry (1874-1936) in 1923. In terms of the Bronsted—Lowry definition, an acid is a proton (H+) donor, and a base is a proton acceptor. For example, when gaseous HCl dissolves in water, each HCl molecule donates a proton to a water molecule, and so HCl qualifies as a Bronsted-Lowry acid. The molecule that accepts the proton—water in this case—is a Bronsted-Lowry base. 

Bronsted-Lowry definition (model) a model proposing that an acid is a proton donor, and a base is a proton acceptor. (7.1)... 

The nucleophile, the ammonia molecule, is also acting as a base, while the electrophile, the proton, is also acting as an acid. So a base may also be thought of as a nucleophile, because both are electron rich species and seek positive centres. The above reaction between the ammonia and the proton may be classified as a Bronsted-Lowry acid/base reaction. It may also be classed as a Lewis acid/base reaction, depending on whether one views the ammonia as a proton acceptor or as a donor of a lone pair of electrons. 

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