Chapter 22, Problem 22.76AP

Interpretation Introduction

(a)

Interpretation:

Whether the resonance interaction increases or decreases the acidity of an $\alpha ,\beta$-unsaturated carboxylic acid is to be stated.

Concept introduction:

Most of the organic structures cannot be represented using a single Lewis structure. Therefore, there exists more than one Lewis structure for representing a molecule or ion. These structures are known as resonance structures. The delocalization of electrons results in the formation of resonance structure.

Interpretation Introduction

(b)

Interpretation:

The reason as to how the $\text{p}{K}_{\text{a}}$ value is consistent with the polar effect of the double bond and the resonance effect of part (a) is to be stated.

Concept introduction:

Most of the organic structures cannot be represented using a single Lewis structure. Therefore, there exists more than one Lewis structure for representing a molecule or ion. These structures are known as resonance structures. The delocalization of electrons results in the formation of resonance structure. The acidity of the compound is measured by the acid dissociation constant. It is represented by the symbol $K_{\text{a}}$. It is also known as ionization constant. In practical terms, it is represented in terms of the logarithm $\text{p}{K}_{\text{a}}=-\log \left(K_{\text{a}}\right)$. More positive the value of $\text{p}{K}_{\text{a}}$, lower is the acidity of the compound. It depends on several other factors.