Chapter 14.7, Problem 14.10PSP

Interpretation Introduction

Interpretation:

$O{H}^{-}$ concentration and $pH$ value has to be calculated for the solution of cyclohexaylamine.

Concept Introduction:

Base ionization constant $K_b$

The equilibrium expression for the ionization of weak base $\text{B}$ will be,

  ${\text{B}}_{\text{(aq)}}{\text{+H}}_{\text{2}}{\text{O}}_{\text{(l)}}\stackrel{}{\to }{\text{HB}}^{\text{+}}{}_{\text{(aq)}}{\text{+OH}}^{\text{-}}{}_{\text{(aq)}}$

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

Where ${\text{K}}_{\text{b}}$ is base ionization constant, $[{\text{OH}}^{-}\text{]}$ is concentration of hydroxide ion, $[{\text{HB}}^{\text{+}}\text{]}$ is concentration of conjugate acid, $[\text{B]}$ is concentration of the base

$[{\text{OH}}^{-}\text{]}$ can be determined from pOH as follows,

  $\text{pOH}\text{=}-\text{log}\left[{\text{OH}}^{-}\right]$

$pH$ of a solution can be determined by the given formula,

  $\begin{array}{l}\text{pH}\text{+}\text{pOH}\text{=}\text{14}\\ \\ pH=\text{14}-pOH\end{array}$