College Chemistry : Lewis, Brønsted-Lowry, and Arrhenius Definitions

Study concepts, example questions & explanations for College Chemistry

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Example Questions

Example Question #1 : Lewis, Brønsted Lowry, And Arrhenius Definitions

Identify the Bronsted-Lowry acid in the following equation:

Possible Answers:

Correct answer:

Explanation:

Recall that a Bronsted-Lowry acid donates a proton. From the equation, we can see that  becomes , which it lost an , or a proton. Thus, water must be the Bronsted-Lowry acid.

Example Question #31 : Acid Base Reactions

Identify the Lewis Base in the following reaction:

Possible Answers:

Correct answer:

Explanation:

Recall that a Lewis base accepts a proton, while a Lewis acid donates a proton. Looking at the equation, we can see that  becomes . Since  accepted a proton, it must be the Lewis base.

Example Question #1 : Lewis, Brønsted Lowry, And Arrhenius Definitions

Which type of acid is defined by its ability to produce hydrogen ions in aqueous solution?

Possible Answers:

Bronsted-Lowry acid

Arrhenius acid

None of these

Lewis acid

Correct answer:

Arrhenius acid

Explanation:

There are three main definitions for acids and bases: the Lewis acids and bases, Bronsted-Lowry acids and bases, and Arrhenius acids and bases.

A Lewis acid is a species which can accept an electron pair from a donor. An example of a Lewis acid is ; as a cation, it can accept an electron pair. A Lewis base is a species which can donate an electron pair. An example of a Lewis base is ; as an anion, it can donate an electron pair.

A Bronsted-Lowry acid is a species which can donate a proton. An example of a Bronsted-Lowry acid is , which can donate its hydrogen ion. A Bronsted-Lowry base is a species which can accept a proton from a donor. An example of a Bronsted-Lowry base is , which can accept a hydrogen ion in order to become water.

An Arrhenius acid is a species which releases hydrogen ions into solution. An example of an Arrhenius acid is . When this compound dissolves in aqueous solution, it produces  and . An Arrhenius base is a species which releases hydroxide ions into solution. An example of an Arrhenius base is . When this compound dissolves in aqueous solution, it produces  and .

Example Question #1 : Lewis, Brønsted Lowry, And Arrhenius Definitions

What is the pH of a   solution?

Possible Answers:

Correct answer:

Explanation:

PH is defined as , where  is hydronium concentration). In order to do this we simply take :

=

Example Question #1 : Lewis, Brønsted Lowry, And Arrhenius Definitions

 

According to the Brønsted-Lowry definition of acids and bases, which species in the reaction are acids?

Possible Answers:

There are no acids in the reaction

Correct answer:

Explanation:

Remember a Brønsted-Lowry acid is defined as a proton donor.

In the forward reaction,  is a proton donor. In the backward reaction,  is the proton donor.

The acids in this reaction are  and .

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