Chapter 16, Problem 16.7P

(a)

Interpretation Introduction

Interpretation:

Balanced equation for the titration reaction titration has to be written.

Concept Introduction:

Titration is an analytical method of quantitative chemical analysis to determine concentration of analyte. A reagent known as titrant is prepared as standard solution of known concentration and volume.

Redox reaction is reaction that includes change in oxidation number of molecule, atom or ion and these changes are due to transfer of electron from one species to another. A complete reaction involves oxidation and reduction.

(b)

Interpretation Introduction

Interpretation:

Cell voltage for ${\text{Fe}}^{\text{3+}}|{\text{Fe}}^{2+}$ couple when $5\text{mL}$, $10\text{mL}$ and $15\text{mL}$ of ascorbic acid has been added has to be calculated.

Concept Introduction:

Nernst equation in electrochemistry is the equation that relates the reduction potential of a reaction to the standard reduction potential value.

Consider a hypothetical reaction as follows:

    $\text{Ox}+{\text{ne}}^{-}\to \text{Red}$

For this reaction, Nernst equation can be written as follows:

    ${\text{E}}_{\text{cell}}={\text{E}}^0-\frac{\text{RT}}{\text{nF}}\text{ln}\frac{{\text{a}}_{\text{Red}}}{{\text{a}}_{\text{Ox}}}$

Here,

${\text{E}}_{\text{cell}}$ is cell potential or electromotive force.

${\text{E}}^{\text{0}}$ is standard reduction potential.

$\text{R}$ is universal gas constant.

$\text{T}$ is temperature of interest in Kelvin scale.

$\text{n}$ is number of electron transfer.

$\text{F}$ is Faraday constant.

${\text{a}}_{\text{red}}$ is activity of the reduced form.

${\text{a}}_{\text{ox}}$ is activity of the oxidized form.