Bronsted-Lowry acid A substance

Bronsted-Lowry acid A substance that can transfer H +... 

In the first reaction, the dihydrogen phosphate acts as a Bronsted-Lowry base, and in the second reaction, it acts as a Bronsted-Lowry acid. A substance that can act as either a Bronsted-Lowry acid or a Bronsted-Lowry base, depending on the circumstances, is called an amphoteric substance. 

Bronsted-Lowry Acid A substance that donates protons, H, in a Bronsted-Lowry acid-base reaction. 

Bronsted-Lowry acid A substance capable of donating protons. See acid-base pair, conjugate proton. Bronsted-Lowry base A substance capable of accepting protons. See proton. 

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. 

Brensted-Lowry acid a substance that donates a proton to another substance dcido de Bronsted-Lowry una... 

A Bronsted-Lowry acid is a substance that donates a proton (H+), and a Bronsted-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 HC1 molecule acts as an acid and donates a proton, while a water molecule acts as a base and accepts the proton, yielding hydronium ion (H30+) and chloride ion (Cl-). 

Bronsted-Lowry acid (Section 2.7) A substance that donates a hydrogen ion (proton H + ) to a base. 

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. 

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. 

If a substance can behave both as a Bronsted-Lowry acid and as a Bronsted-Lowry base then it is called amphoteric. Water has this ability. As well as reacting with acids (above) it can also react with Bronsted-Lowry bases such as ammonia in the following way to form the base OH ... 

A Bronsted-Lowry acid is a substance that transfers a proton to another substance. Since a hydrogen ion is a proton, all Arrhenius acids are Bronsted-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 ... 

Another significant difference between definitions is that Bronsted-Lowry acids and bases need not be molecular substances. There are a variety of reactions in which ions donate or accept protons. In the sample below, note how the cyanide ion (CN-) acts as a base by accepting a proton and the bicarbonate ion (HC03 ) acts as an acid by donating a proton ... 

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 ... 

The Lewis concept deals with the behavior of electron pairs in chemical reactions. The same electron pairs we looked at when we discussed molecular geometry (see Chapter 7) can be involved in many reactions. Substances that can form a covalent bond by accepting an electron pair from another substance are known as Lewis acids. Substances that can form a covalent bond by donating an electron pair to another substance are known as Lewis bases. Be careful that you don t mix these up with the Bronsted-Lowry acids and bases. It is easy to do since the words donate and accept are used, except they are associated with the opposite species (Bronsted-Lowry acids donate protons, while Lewis acids accept electron pairs). 

The correct answer is (C). With the exception of choice (C), all of the substances can either donate a proton, or accept one. NH4+ can only lose an electron. It cannot gain. one, so it is only a Bronsted-Lowry acid. 

The idea of proton transfer has major implications for understanding the nature of acids and bases. According to the Bronsted-Lowry theory, any substance can behave as an acid, but only if another substance behaves as a base at the same time. Similarly, any substance can behave as a base, but only if another substance behaves as an acid at the same time. 

A Bronsted-Lowry acid is any substance that is capable of donating a proton, whereas a Bronsted-Lowry base is any substance that is capable of accepting a proton. The loss of a proton by an acid gives rise to an entity that is a potential proton acceptor and thus a base it is called the conjugate base of the parent acid. Examples of acids reacting with bases are given in Table 1.16. The reactions listed in Table 1.16 are spontaneous in the direction that favors production of the weaker acid and base. Compounds that may act as bases and acids are referred to as amphoteric. 

Acids and bases were defined and described by early chemists, including Boyle, Lavoisier, Davy, Berzelius, Liebig, and Arrhenius. At the present time, depending on objectives, one of two definitions of acids and bases is likely to be accepted. These two definitions, by Bronsted and Lowry and by Lewis, were proposed about the same time. According to the Bronsted definition acids are substances having a tendency to lose a proton, and bases are those having a tendency to accept a proton. Thus, for an acid HA the acid-base half-reaction is... 

A broader definition of acids and bases, which will be useful in quantitative calculations in this chapter, was proposed independently by Johannes Bronsted and Thomas Lowry in 1923. A Brensted-Lowry acid is defined as a substance that can donate a hydrogen ion, and a Bronsted-Lowry base is a substance that can accept a hydrogen ion. In a Bronsted-Lowry acid-base reaction, hydrogen ions are transferred from the acid to the base. When acetic acid is dissolved in water,... 

Some substances can act as a Bronsted-Lowry acid in one reaction and a Bronsted-Lowry base in another. Consider the following net ionic equations for the reaction of dihydrogen phosphate ion with either the acid hydrochloric acid or the strong base hydroxide. 

Because both dihydrogen phosphate and hydrogen carbonate (and other substances like them) can be either Bronsted-Lowry acids or bases, they cannot be described as a Bronsted-Lowry acid or base except with reference to a specific acid-base reaction. For this reason, the Arrhenius definitions of acids and bases are the ones used to categorize isolated substances on the stockroom shelf A substance generates either hydronium ions, hydroxide ions, or neither when added to water, so it is always either an acid, a base, or neutral in the Arrhenius sense. Hydrogen carbonate is an Arrhenius base because it yields hydroxide ions when added to water. Dihydrogen phosphate is an Arrhenius acid because it generates hydronium ions when added to water. 

Amphoteric substance A substance that can act as either a Bronsted-Lowry acid or a Bronsted-Lowry base, depending on the circumstances. 

Explain why a substance can be a Bronsted-Lowry acid in one reaction and a Objective 29... 

One of the substances that give wet goats and dirty gym socks their characteristic odors is hexanoic acid, CFf3CFl2CFf2CFf2CFf2C02Ff, which is a monoprotic weak acid. Write the formula for the conjugate base of this acid. Write the equation for the reaction between this acid and water, and indicate the Bronsted-Lowry acid and base for the forward reaction. (The acidic hydrogen atom is on the right side of the formula.)... 

The Bronsted-Lowry acid-base definitions are based on the amphiprotic properties of water Water is capable of acting as both a hydrogen ion donor and a hydrogen ion acceptor, depending on the acidic or basic properties of the dissolved substance (equations 9 and 10). Water can also act as a proton donor and proton acceptor towards itself This is referred to as the autoionization of water. 

Ammonia—a Bronsted-Lowry base All of the acids and bases that fit the Arrhenius definition of acids and bases also fit the Bronsted-Lowry definition. But some other substances that lack a hydroxide group and, therefore, cannot be considered bases according to the Arrhenius definition can be classified as acids according to the Bronsted-Lowry model. One example is ammonia (NHsj.When ammonia dissolves in water, water is a Bronsted-Lowry acid in the forward reaction. Because the NH3 molecule accepts a H+ ion to form the ammonium ion (NH4+), ammonia is a Bronsted-Lowry base in the forward reaction. 

Water—a Bronsted-Lowry acid and base Recall that when HF dissolves in water, water acts a base when NH3 dissolves in water, water acts as an acid. Depending on what other substances are in the solution, water can act as either an acid or a base. Water and other substances that can act as both acids and bases are said to be amphoteric. 

Perhaps you will not be surprised, then, you to learn that an even more general model of acids and bases was proposed by American chemist G. N. Lewis (1875-1946). Recall that Lewis developed the electron-pair theory of chemical bonding and introduced Lewis structures to keep track of the electrons in atoms and molecules. He applied his electron-pair theory of chemical bonding to acid-base reactions. Lewis proposed that an acid is an ion or molecule with a vacant atomic orbital that can accept (share) an electron pair. A base is an ion or molecule with a lone electron pair that it can donate (share). According to the Lewis model, a Lewis acid is an electron-pair acceptor and a Lewis base is an electron-pair donor. Note that the Lewis model includes all the substances classified as Bronsted-Lowry acids and bases and many more. 

Q A Bronsted-Lowry acid is a substance that donates an H ion (a proton) to another species. 

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