Chapter 15, Problem 15.28P

(a)

Interpretation Introduction

Interpretation:

Reason behind rise in curve observed at low $\text{pH}$ has to be given.

Concept Introduction:

Liquid- ion-selective electrode is composed of the hydrophobic ion-selective membrane that is essentially an organic polymer. This thin membrane is filled with a viscous ion exchanger solution. The purpose of this solution is to selectively bond the analyte ion. Selectivity of the bound analyte can be mathematically measured with the use of selectivity coefficient.

Potential difference for ion selective electrode is evaluated by expression as follows:

  $E=\frac{0.05916}{n}\left[\log \left({\left[{\text{C}}^{+}\right]}_{\text{outer 2}}\right)-\log \left({\left[{\text{C}}^{+}\right]}_{\text{outer 1}}\right)\right]$

Here,

${\left[{\text{C}}^{+}\right]}_{\text{outer 2}}$ denotes concentration of analyte solution 2.

${\left[{\text{C}}^{+}\right]}_{\text{inner}}$ denotes concentration of analyte solution 1.

$n$ denotes charge on analyte.

$E$ denotes potential difference.

(b)

Interpretation Introduction

Interpretation:

Reason behind fall in curve observed at high $\text{pH}$ has to be given.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

Optimum $\text{pH}$ for ${\text{NO}}_2^{-}$ ion based ion-selective electrode has to be given.

Concept Introduction:

Refer to part (a).

(d)

Interpretation Introduction

Interpretation:

Lower concentration limit for linear response has to be calculated.

Concept Introduction:

Refer to part (a).