Chapter 5.3, Problem 12E

(a)

Interpretation Introduction

Interpretation: The structure of the conjugate acid of monosodium phosphate (base) needs to be determined.

Concept Introduction:Bronsted and Lowry purposed the 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.

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

(b)

Interpretation Introduction

Interpretation: The reason of ineffective use of an aqueous solution of monosodium phosphate for extracting benzoic acid from a diethyl ether solution needs to be explained, if the pKa of conjugate acid of monosodium phosphate is 2.1.

  

Concept Introduction:Bronsted and Lowry purposed the 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.

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