Chapter 14, Problem 14.23QAP

Interpretation Introduction

(a)

Interpretation:

The formation constant and the difference in molar absorptivities at 470 nm should be determined using linear regression and the Benesi-Hildebrand equation.

Concept introduction:

The Benesi-Hildebrand equation is:

$\frac{b}{\Delta A}=\frac{1}{\Delta \epsilon K_f{C}_M}.\frac{1}{C_L}+\frac{1}{\Delta \epsilon C_M}$

b − length of the solution light passes through

ΔA − difference between absorbance with and without the ligand present

Δe − difference of the molar absorptivities of complex and metal ion.

K_f − formation constant

C_M − concentration of metal ion

C_L − concentration of ligand.

Interpretation Introduction

(b)

Interpretation:

The values of K_f and Δe should be determined using non-linear regression.

Concept introduction:

$\frac{\Delta A}{b}=\frac{\Delta \epsilon K_f{C}_L{C}_M}{1+K_f{C}_L}$

b − length of the solution light passes through

ΔA − difference between absorbance with and without the ligand present

Δe − difference of the molar absorptivities of complex and metal ion.

K_f − formation constant

C_M − concentration of metal ion

C_L − concentration of ligand.