Chapter 6, Problem 6D.4E

(a)

Interpretation Introduction

Interpretation:

The ${\text{K}}_{\text{a}}$ and ${\text{pK}}_{\text{a}}$ value of 0.015 M aqueous solution of nitrous acid has to be calculated when the pH value of 0.015 M nitrous acid is 2.63.

Concept introduction:

pH definition:

The concentration of hydrogen ion is measured using $\text{pH}$ scale.  The acidity of aqueous solution is expressed by $\text{pH}$ scale.

The $\text{pH}$ of a solution is defined as the negative base-10 logarithm of the hydrogen or hydronium ion concentration.

  $\text{pH}\text{=}{\text{-log[H}}_{\text{3}}{\text{O}}^{\text{+}}\text{]}$

On rearranging, the concentration of hydrogen ion ${\text{[H}}^{+}\text{]}$ can be calculated using pH as follows,

  ${\text{[H}}^{+}\text{]}\text{=}{\text{10}}^{\text{-pH}}$

(b)

Interpretation Introduction

Interpretation:

The ${\text{K}}_{\text{b}}$ and ${\text{pK}}_{\text{b}}$ value of 0.10 M aqueous solution of butylamine has to be calculated when the pH value of 0.10 M butylamine is 12.04.

Concept introduction:

Refer to part (a).