Chapter 2.3, Problem 2.14E

Interpretation Introduction

Interpretation: The reason behind existence of glycine in the form of ${}^{+}{\text{H}}_3{\text{NCH}}_2{\text{COO}}^{-}$ should be accounted by the help of value of $K_{\text{a}}$ for reaction between ammonia and acetic acid.

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.