Chapter 15, Problem 1RQ

Interpretation Introduction

Interpretation:

Difference that can exist between Arrhenius and Bronsted-Lowry definitions of an acid has to be written.

Concept Introduction:

Arrhenius gave broader picture and suggested that acids are able to release excess of ${\text{H}}^{+}$ ion on dissolution in water while bases are able to release excess of ${\text{OH}}^{-}$ ion on dissolution in water.

Bronsted-Lowry acid outlined the definition of acids that donate ${\text{H}}^{+}$ or a proton while bases that accept ${\text{H}}^{+}$ or a proton. The acidic strength is known from the ability of acid to donate ${\text{H}}^{+}$ in an aqueous solution. Explicitly the acidity strength is quantified by the magnitude of a parameter called acid ionization constant. The strong acids tend to possess higher magnitudes of acid ionization constant or $K_{\text{a}}$.

Explanation of Solution

In accordance with Bronsted definition, the most usual type of acid-base reaction involves lone pair of base that reaches out for an acidic proton. Once deprotonation has occurred species assumes a negative charge and is referred to as the conjugate base of acid and other species with a positive charge as a result of proton acceptance is termed conjugate acid of given base. For example;

In Arrhenius concept, the acid species is one that can make water to behave as Bronsted base so that it accepts the proton and forms ${\text{H}}_3{\text{O}}^{+}$ as illustrated below.

Thus all Arrhenius acid are capable to act as Bronsted acid.