Hydrogen ions , Brpnsted-Lowry acid

A Br0nsted-Lowry base is to a hydrogen-ion acceptor as a Brpnsted-Lowry acid is to —... 

The hydrogen ion accepts the lone pair of electrons from the ammonia to form the ammonium ion. The hydrogen ion, because it accepts a pair of electrons, is the Lewis acid. The ammonia, because it donates a pair of electrons, is the Lewis base. This reaction is also a Brpnsted-Lowry acid-base reaction. This illustrates that a substance may be an acid or a base by more than one definition. All Brpnsted-Lowry acids are Lewis acids, and all Brpnsted-Lowry bases are Lewis bases. However, the reverse is not necessarily true. 

The carboxylic acids, like all Brpnsted-Lowry acids, can lose a hydrogen ion. The result is a carboxylate ion, shown in Figure 9-4. 

In this reaction, hydrochloric acid (HCl) donates a proton to water (H2O), making it the Brpnsted-Lowry acid. Water, which accepts the proton, is the Bronsted-Lowry base. This makes hydronium (H3O+) the conjugate acid and chloride (Cl ) the conjugate base. Water can act as the base in this reaction and as an acid in the example problem because it s composed of both a hydrogen ion and a hydroxide ion therefore, it can either accept or donate a proton. 

Brpnsted-Lowry acid A proton (hydrogen ion) donor. 

In 1923, the Danish chemist Johannes Brpnsted proposed a broader definition of acid. Surprisingly, the same year, the British scientist Thomas Lowry happened to make exactly the same proposal independently. Their idea was to apply the name acid to any species that can donate a proton. Recall that a proton is a hydrogen atom that has lost its electron it is a hydrogen ion and can be represented as Ht Such molecules or ions are now called Brunsted-Lowry acids. A reaction showing hydrochloric acid, a representative Brpnsted-Lowry acid, is depicted in Figure 7. 

When a Brpnsted-Lowry acid donates a hydrogen ion, a conjugate base is formed when a Brpnsted-Lowry base accepts a hydrogen ion, a conjugate acid is formed. 

The next theory of acids and bases is called the Brpnsted-Lowry Theory, proposed by Danish chemist Johannes Brpnsted and the English chemist Thomas Lowry, independently, in 1923. The definition of an acid, in this theory, sounds essentially the same as the Arrhenius acid. ABr0nsted-Lowry acid is defined as a substance that donates a proton to another species. Now, you might say, A proton is a hydrogen ion (H+), so what is the difference between the two definitions for acids Most notably, this definition doesn t require that the acid be in an aqueous solution. So a substance that donates protons, even when in a solid or vapor phase, is still acting as a Brpnsted-Lowry acid. 

A Br ousted-Lowry acid is a substance that transfers a proton to another substance. Since a hydrogen ion is a proton, all Arrhenius acids are Brpnsted-Lowry acids. However, the slight difference in definitions allows us to consider additional substances as acids. We can also consider reactions that do not occur in aqueous solutions. 

From this you can see that the cahon from the salt comes from the base and the anion comes from the acid. Salts can act as Brpnsted-Lowry acids or bases to produce solutions that are acidic or basic. The salts react with water in a reachon known as hydrolysis to yield either a conjugate acid and a hydroxide ion or a conjugate base and a hydrogen (hydroiuum) ion. If you know the origins of the components of a salt, you can make some predichons about the pH of the solution formed from a hydrolysis of a salt ion. 

Water is the base in this reaction. Acid and base reactions in general chemistry are always done in water. When a Brpnsted-Lowry acid such as HCl is placed in water, a proton is transferred to a water molecule (water is the base) a conjugate acid is formed (the hydronium ion HgO+) as well as a conjugate base (the chloride ion). In neutral pure water (no acid is present), the hydrogen ion concentration is about 1.0 x 10 M (pH of 7). An increase in the concentration of hydrogen ions above 1.0 x 10 M gives an acidic solution, with a pH less than 7. If the pH is greater than 7, it is considered a basic solution. 

Blood contains several substances that minimize changes in its acidity by reacting with either an acid or a base. One of these is the hydrogen phosphate ion, HP04. Write one equation showing this species acting as a Brpnsted—Lowry acid and another in which the species acts as a Brpnsted— Lowry base. 

Clearly, the two reactions are analogous and demonstrate that the reaction between hydroxide ion and hydrogen bromide is simultaneously a Brpnsted-Lowry acid-base reaction and a Lewis acid/Lewis base reaction. Br0nsted-Lowry acid-base reactions constitute a subcategory of Lewis acid/Lewis base reactions. 

In this reaction hydrogen chloride donates a proton therefore it acts as a Brpnsted-Lowry acid. Water accepts a proton from hydrogen chloride thus water serves as a Brpnsted-Lowry base. The products are a hydronium ion (HsO" ) and chloride ion (C ). 

A Brpnsted-Lowry acid is a substance that donates a proton (H" "), and a Brpnsled-Lowry base is a substance that accepts a proton. (The name proton is often used as a synonym for hydrogen ion, H" ", because loss of the valence electron from a neutral hydrogen atom leaves only the hydrogen nucleus— a proton.) When gaseous hydrogen chloride dissolves in water, for example, a polar HCl molecule acts as an acid and donates a proton, while a water molecule acts as a base and accepts the proton, yielding hydronium ion (HsO" ") and chloride ion (Cl ). 

Brpnsted-Lowry acids and bases An acid is a hydrogen ion donor a base is a hydrogen ion acceptor. 

In 1923, J. N. Br0nsted in Denmark and T. M. Lowry in Great Britain expanded the definition of acids and bases to include bases that do not contain OH ions. A Brpnsted-Lowry acid can donate a hydrogen ion (H ) to another substance, and a Brpnsted-Lowry base can accept a hydrogen ion (H+). 

A hydrogen ion is donated by HCIO2, which is the Brpnsted-Lowry acid in the forward reaction. The resulting conjugate base is C102. The base in the forward reaction is H2O, which accepts a hydrogen ion to form the conjugate acid HjO. ... 

All Brpnsted-Lowry and Arrhenius acids contain hydrogen. The formation or transfer of hydrogen ions is the key to the behavior of all acids. You may wish to review the behavior of acids in Chapters 4 and 15. 

A particularly important concept in chemistry is that associated with proton loss and gain, i.e. acidity and basicity. Acids produce positively charged hydrogen ions H+ (protons) in aqueous solution the more acidic a compound is, the greater the concentration of protons it produces. In water, protons do not have an independent existence, but become strongly attached to a water molecule to give the stable hydronium ion H3O+. In the Brpnsted-Lowry definition ... 

Brpnsted-Lowry definition does not differ appreciably from the Arrhenius definition of hydrogen ions (acids) and hydroxide ions (bases) ... 

The work of Brpnsted and Pedersen (23) on the catalytic decomposition of nitramide and the kinetic studies of Lowry and Faulkner (24) on the mutarotation of tetramethylglucose led to the formulation of a more general viewpoint on acids and bases which logically showed that the hydrogen ion and hydroxyl ion were not the unique carriers of acid and basic properties. An acid was defined as any substance capable of donating a proton, and a base any substance capable of accepting a proton. In accordance with this definition (Lowry, 25 Brpnsted, 26), the following substances are typical acids and bases ... 

The Bronsted-Lowry model The Danish chemist Johannes Brpnsted and the English chemist Thomas Lowry independently proposed a more inclusive model of acids and bases—a model that focuses on the hydrogen ion (H+). In the Bronsted-Lowry model of acids and bases, an acid is a hydrogen-ion donor and a base is a hydrogen-ion acceptor. 

The correct answer is (C). Bases in this reaction would be considered the substances that are accepting protons (Brpnsted-Lowry definition). In the forward reaction, H,0 receives a hydrogen to become a hydronium ion. In the reverse reaction, CN" receives a proton to become HCN. HCN donates a proton, which makes it an acid. 

According to the theory proposed by Svante Arrhenius, a Swedish chemist and winner of the 1903 Nobel Prize in chemistry, an acid ionizes in aqueous solution to liberate protons (H, hydrogen ions), whereas bases ionize to liberate hydroxide ions (HO ). A more general theory of acids and bases was devised independently by Johannes Brpnsted (Denmark) and Thomas M. Lowry (England) in 1923. In the Brpnsted-Lowry approach, an acid is a proton donor, and a base is a proton acceptor. 

The definitions of acid and base that we use now were provided by Brpnsted and Lowry in 1923. In the Br0nsted-Lowry definitions, an acid is a species that donates a proton, and a base is a species that accepts a proton. (Remember that positively charged hydrogen ions are also called protons.) In the following reaction, hydrogen chloride (HCl) meets the Brpnsted-Lowry definition of an acid because it donates a proton to water. Water meets the definition of a base because it accepts a proton from HCl. Water can accept a proton because it has two lone pairs. Either lone pair can form a covalent bond with a proton. In the reverse reaction, H3O is an acid because it donates a proton to CF, and CF is a base because it accepts a proton from H30. ... 

Br0nsted and Lowry defined an add as a species with a tendency to lose a hydrogen ion and a base as a species with a tendency to gain a hydrogen ion. For example, the Brpnsted-Lowry reaction of a strong acid with the weak base nitrite in aqueous solution would be ... 

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