Chapter 2.3, Problem 2.17TIY

(a)

Interpretation Introduction

Interpretation: Among acetic and benzoic acid the stronger acid should be determined and factor by which their acidity differ is to be calculated.

Concept introduction: The formula to calculate $K_{\text{a}}$ from $\text{p}{K}_{\text{a}}$ is given as follows:

  $K_{\text{a}}={10}^{-\text{p}{K}_{\text{a}}}$

Where,

• $K_{\text{a}}$ denotes dissociation constant of acid.

(b)

Interpretation Introduction

Interpretation: Among acetic and trichloroacetic acid, the stronger acid should be determined on the basis of structures.

Concept introduction: The formula to calculate $K_{\text{a}}$ from $\text{p}{K}_{\text{a}}$ is given as follows:

  $K_{\text{a}}={10}^{-\text{p}{K}_{\text{a}}}$

Where,

  $K_{\text{a}}$ denotes dissociation constant of acid.

Smaller the magnitude of $\text{p}{K}_{\text{a}}$ greater is the acidic strength and vice-versa. This is because the relation between $K_{\text{a}}$ from $\text{p}{K}_{\text{a}}$ is inversely related to each other. The acid will smaller $\text{p}{K}_{\text{a}}$ will have more dissociation and thus would act as a stronger acid.