Chapter 14, Problem 14.90SP

Interpretation Introduction

Interpretation:

The values of ${\text{K}}_{\text{b}}$ and ${\text{pK}}_{\text{b}}$, when the $\text{pH}$ of a $\text{7}{\text{.0×10}}^{\text{-4}}\text{ M}$ solution of Morphine $\left({\text{C}}_{\text{17}}{\text{H}}_{\text{19}}{\text{NO}}_{\text{3}}\right)$ is $9.50$ has to be determined.

Concept Introduction:

Consider a reaction of weak base,

${\text{B+H}}_{\text{2}}\text{O}\stackrel{{\text{K}}_{\text{b}}}{\rightleftharpoons }{\text{BH}}^{\text{+}}{\text{+OH}}^{\text{-}}$

The base dissociation constant ${\text{K}}_{\text{b}}$ can be given as,

${\text{K}}_{\text{b}}\text{=}\frac{\left[{\text{BH}}^{\text{+}}\right]\left[{\text{OH}}^{\text{-}}\right]}{\left[\text{B}\right]}$

Where ${\text{K}}_{\text{b}}$ is called as base dissociation constant.

The ${\text{pK}}_{\text{b}}$ can be calculated as given below.

${\text{pK}}_{\text{b}}\text{= -log}\left({\text{K}}_{\text{b}}\right)$