Chapter 19, Problem 19.14P

Interpretation Introduction

Interpretation:

Graph of $\text{log}\left[\left(A-A_{\text{HIn}}\right)\text{/}\left(A_{\text{In}}-A\right)\right]$ versus $\text{pH}$ has to be written.

Concept Introduction:

Expression to compute absorbance as per Beer’s law is as follows:

  $A=\epsilon \cdot b\cdot c$

Here,

$\epsilon$ denotes molar absorptivity of species capable top absorb.

$b$ denotes path length in centimeters.

$c$ denotes concentration of species capable top absorb

$A$ denotes absorbance.

$T$ denotes transmittance.

Expression for $\text{HIn}$ as per Beer’s law is as follows:

  $A_{\text{HIn}}={\epsilon }_{\text{HIn}}\cdot b\cdot \left[\text{HIn}\right]$

Expression for ${\text{In}}^{-}$ as per Beer’s law is as follows:

  $A_{{\text{In}}^{-}}={\epsilon }_{{\text{In}}^{-}}\cdot b\cdot \left[{\text{In}}^{-}\right]$

Thus, Beer’s law expression for mixture is as follows:

  $A={\epsilon }_{\text{HIn}}\cdot b\cdot \left[\text{HIn}\right]+{\epsilon }_{{\text{In}}^{-}}\cdot b\cdot \left[{\text{In}}^{-}\right]$