Chapter 19, Problem 19.48P

Interpretation Introduction

(a)

Interpretation: The explanation corresponding to the given statement that the $\text{p}{K}_{\text{a}}$ for loss of the first proton $\left(\text{p}{K}_{\text{a1}}\right)$ is lower for phthalic acid than isophthalic acid is to be stated.

Concept introduction: The $\text{p}{K}_{\text{a}}$ value and acidic strength are inversely related to each other. The major factors that contribute to the acidic strength are inductive effect and polarity. There are two types of inductive effects named as positive and negative inductive effect. Positive inductive effect lowers the acidic strength of the compounds, whereas negative inductive effect increases the acidic strength of the compounds. The elimination of a proton leads to the formation of a conjugate base.

Interpretation Introduction

(b)

Interpretation: The explanation corresponding to the given statement that the $\text{p}{K}_{\text{a}}$ for loss of the second proton $\left(\text{p}{K}_{\text{a2}}\right)$ is higher for phthalic acid than isophthalic acid is to be stated.

Concept introduction: The $\text{p}{K}_{\text{a}}$ value and acidic strength are inversely related to each other. The major factors that contribute to the acidic strength are inductive effect and polarity. There are two types of inductive effects named as positive and negative inductive effect. Positive inductive effect lowers the acidic strength of the compounds, whereas negative inductive effect increases the acidic strength of the compounds. The elimination of a proton leads to the formation of a conjugate base.