Chapter 18, Problem 18.109P

(a)

Interpretation Introduction

Interpretation:

The ${\text{pK}}_{\text{b}}$ of ${\text{NO}}_{\text{2}}^{\text{-}}$ ion has to be calculated.

Concept introduction:

The ${\text{K}}_a$ and ${\text{K}}_{\text{b}}$ value is calculating by using following formula,

  ${\text{K}}_{\text{w}}{\text{ = K}}_{\text{a}}{\text{ × K}}_{\text{b}}$

The base - dissociation constant can be expressed as ${\text{pK}}_{\text{b}}$ values,

  $\begin{array}{l}{\text{pK}}_{\text{b}}{\text{ = -log K}}_{\text{b}}\text{ and}\\ {\text{10}}^{{\text{ - pK}}_{\text{b}}}{\text{ = K}}_{\text{b }}\end{array}$

(b)

Interpretation Introduction

Interpretation:

The ${\text{pK}}_a$ of hydrazinium ion (${\text{H}}_{\text{2}}{\text{NNH}}_{\text{3}}^{\text{+}}$) has to be calculated.

Concept introduction:

The relationship between ${\text{pK}}_{\text{a}}{\text{ and pK}}_{\text{b}}$ is given below,

  ${\text{pK}}_{\text{a}}{\text{ + pK}}_{\text{b}}\text{ =14}\text{.00 }$

The ${\text{K}}_a$ and ${\text{K}}_{\text{b}}$ value is calculating by using following formula,

  ${\text{K}}_{\text{w}}{\text{ = K}}_{\text{a}}{\text{ × K}}_{\text{b}}$

The acid-dissociation constant can be expressed as ${\text{pK}}_a$ values,

  $\begin{array}{l}{\text{pK}}_a{\text{ = -log K}}_a\text{ and}\\ {\text{10}}^{{\text{ - pK}}_a}{\text{ = K}}_{\text{a }}\end{array}$