Chapter 7, Problem 83E

Interpretation Introduction

Interpretation: The value of pH of 10.0 mL solution that contains 5.0 mg of codeine needs to be determined. The ${\text{pK}}_{\text{b}}$ of codeine is 6.05 and the molecular formula of codeine is ${\text{C}}_{\text{18}}{\text{H}}_{\text{21}}{\text{NO}}_{\text{3}}$ .

Concept Introduction: A base is the substance that gives ${\text{OH}}^{\text{-}}$ ions in its aqueous solution. On the basis of base dissociation, they can be classified as strong and weak base. A strong base is ionized completely and gives the respective ions.

  ${\text{BOH}}_{\text{(aq)}}\stackrel{}{\to }{\text{B}}^{+}{}_{\text{(aq)}}+{\text{OH}}^{\text{-}}{}_{\text{(aq)}}$

On the contrary, a weak base ionized partially and reaches to equilibrium.

  ${\text{B}}_{\text{(aq)}}{\text{ + H}}_{\text{2}}{\text{O}}_{\text{(aq)}}\rightleftharpoons {\text{ HB}}^{\text{+}}{}_{\text{(aq)}}{\text{ + OH¯}}_{\text{(aq)}}$