Chapter 14.1, Problem 14.3CP

Interpretation Introduction

Interpretation:

For given reaction in aqueous solution, Bronsted-Lowry acid-base and conjugate acid-base pairs has to be identified.

Concept introduction:

Bronsted-Lowry acid and bases:

The chemical species which is able to donate hydrogen ion to other substance is known as B-L acid and the species which is able to accept hydrogen ion from another species is known as B-L base.

Example for B-L acid: Hydrochloric acid $\text{(HCl)}$, Acetic acid ${\text{(CH}}_{\text{3}}\text{COOH)}$ and Ammonium cation ${\text{(NH}}^{\text{+}}\text{)}$

${\text{HCl+H}}_{\text{2}}\text{O}\stackrel{}{\to }{\text{Cl}}^{\text{+}}{\text{+H}}_{\text{3}}{\text{O}}^{\text{+}}$

Where, Hydrochloric acid donates hydrogen ion to water (B-L base).  Hence, $\text{HCl}$ is (B-L acid) and water is B-L base.

Conjugate acid-base pair:

By gain or loss of ${\text{H}}^{\text{+}}$ conjugate acid-bases are related to each other.

Consider acid $\text{HA}$ with its corresponding base ${\text{A}}^{\text{-}}$ they are collectively known as conjugate acid-base pair since they are associated with gain or loss of proton.

Conjugate base of weak acid is a weak base.

Conjugate acid of weak base is a weak acid.