Chapter 23, Problem 23.15P

(a)

Interpretation Introduction

Interpretation:

The expression for the fraction of metal ion extracted into the organic phase in terms of distribution coefficient $\left(\text{D}\right)$ and volumes of two phases has to be given.

Concept introduction:

Distribution of metal-chelate complex:

Distribution of metal-chelate complex between phases is given by

$\begin{array}{l}\text{D}\approx \frac{{\text{K}}_{\text{M}}{\text{βK}}_{\text{a}}^{\text{n}}}{{\text{K}}_{\text{L}}^{\text{n}}}\frac{{\left[\text{HL}\right]}_{\text{org}}^{\text{n}}}{{\left[{\text{H}}^{\text{+}}\right]}_{\text{aq}}^{\text{n}}}\\ \text{where,}\\ \text{D}\text{-}\text{distribution}\text{coefficient}\\ {\text{K}}_{\text{M}}\text{-}\text{partition}\text{coefficient}\text{for}\text{metal}\\ {\text{K}}_{\text{L}}\text{-}\text{partition}\text{coefficient}\text{for}\text{ligand}\\ \text{β}\text{-}\text{formation}\text{constant}\\ {\text{K}}_{\text{a}}\text{-}\text{acid}\text{dissociation}\text{constant}\end{array}$

(b)

Interpretation Introduction

Interpretation:

A graph of the percentage of metal ion extracted over the pH range of $\text{0}\text{to}\text{5}$ has to be given.

Concept introduction:

Distribution of metal-chelate complex:

Distribution of metal-chelate complex between phases is given by

$\begin{array}{l}\text{D}\approx \frac{{\text{K}}_{\text{M}}{\text{βK}}_{\text{a}}^{\text{n}}}{{\text{K}}_{\text{L}}^{\text{n}}}\frac{{\left[\text{HL}\right]}_{\text{org}}^{\text{n}}}{{\left[{\text{H}}^{\text{+}}\right]}_{\text{aq}}^{\text{n}}}\\ \text{where,}\\ \text{D}\text{-}\text{distribution}\text{coefficient}\\ {\text{K}}_{\text{M}}\text{-}\text{partition}\text{coefficient}\text{for}\text{metal}\\ {\text{K}}_{\text{L}}\text{-}\text{partition}\text{coefficient}\text{for}\text{ligand}\\ \text{β}\text{-}\text{formation}\text{constant}\\ {\text{K}}_{\text{a}}\text{-}\text{acid}\text{dissociation}\text{constant}\end{array}$