Chapter 9, Problem 36P

Interpretation Introduction

(a)

Interpretation:

The conjugated acid of amphoteric ${\text{H}}_{\text{2}}{\text{PO}}_4{}^{\text{-}}$ ion needs to be determined.

Concept Introduction:

A substance is said to be acidic if it can give hydrogen ions ( ${\text{H}}^{\text{+}}$ ) whereas a base is said to be a substance that can give ${\text{OH}}^{\text{-}}$ ion. This theory of acid and base is called the Arrhenius theory of acid and base.

Another theory that is purposed by Bronsted and Lowery is called Bronsted-Lowry acid-base theory. It states that acid can give ${\text{H}}^{\text{+}}$ ions whereas a base can accept the ${\text{H}}^{\text{+}}$ ion in its solution. Hence this theory is entirely based on the presence of ${\text{H}}^{\text{+}}$ ion in the given substance. It purposed the concept of conjugated acid-base pair. A Bronsted acid gives ${\text{H}}^{\text{+}}$ ion to form conjugated base whereas a Bronsted base accepts ${\text{H}}^{\text{+}}$ ion to form its conjugated acid.

  $\begin{array}{l}{\text{ HA + H}}_{\text{2}}\text{O }\underset{}{\to }{\text{ A}}^{\text{-}}{\text{ + H}}_{\text{3}}{\text{O}}^{\text{+}}\\ \text{Bronsted + Bronsted Conjugated Conjugated}\\ \text{ Acid base base acid}\end{array}$

The term amphoteric stands for both acidic and basic behavior of ion.

Interpretation Introduction

(b)

Interpretation:

The conjugated base of ${\text{H}}_{\text{2}}{\text{PO}}_4{}^{\text{-}}$ ion needs to be determined.

Concept Introduction:

A substance is said to be acidic if it can give hydrogen ions ( ${\text{H}}^{\text{+}}$ ) whereas a base is said to be a substance that can give ${\text{OH}}^{\text{-}}$ ion. This theory of acid and base is called the Arrhenius theory of acid and base.

Another theory that is purposed by Bronsted and Lowery is called Bronsted-Lowry acid-base theory. It states that acid can give ${\text{H}}^{\text{+}}$ ions whereas a base can accept the ${\text{H}}^{\text{+}}$ ion in its solution. Hence, this theory is entirely based on the presence of ${\text{H}}^{\text{+}}$ ion in the given substance. It purposed on the concept of conjugated acid-base pair. A Bronsted acid gives ${\text{H}}^{\text{+}}$ ion to form conjugated base whereas, a Bronsted base accepts ${\text{H}}^{\text{+}}$ ion to form its conjugated acid.

  $\begin{array}{l}{\text{ HA + H}}_{\text{2}}\text{O }\underset{}{\to }{\text{ A}}^{\text{-}}{\text{ + H}}_{\text{3}}{\text{O}}^{\text{+}}\\ \text{Bronsted + Bronsted Conjugated Conjugated}\\ \text{ Acid base base acid}\end{array}$