Chapter 19, Problem 40E

Interpretation Introduction

(a)

Interpretation:

The balanced chemical equation for the oxidation of ${\text{Cl}}^{-}\left(aq\right){\text{ to Cl}}_{\text{2}}\left(g\right)$ by ${\text{PbO}}_{\text{2}}\left(s\right)$ in an acidic solution should be written and whether the reaction occurs spontaneously in the forward direction at [H⁺] = 6.0 M should be explained.

Concept introduction:

In an electrochemical cell, there are two electrodes that can be observed.

If oxidation takes place on an electrode, that electrode is called anode. The species in that electrode remove electrons and itself gets oxidized.

If reduction takes place on an electrode, that electrode is called cathode. The species in that electrode absorbs electrons and itself gets reduced.

The electrode potential of cell can be calculated as follows:

$E^0{}_{\text{cell}}=E^0{}_{\text{cathode}} -E^0{}_{\text{anode}}$

Nernst equation for a cell can be represented as follows:

${\text{E}}_{cell}={\text{E}}^0{}_{cell}-\frac{0.0592\text{ V}}{\text{z}}\text{ log Q}$

Here,

z = number of moles of electrons transferred in the cell and Q is ratio of concentration of products to reactant in a cell.

If E _cell is positive, a reaction occurs spontaneously in the forward direction for the stated conditions.

If E _cell is negative, the reaction occurs spontaneously in the reverse direction for the stated conditions.

If the E _cell = 0 reaction is at equilibrium for the stated conditions.

Interpretation Introduction

(b)

Interpretation:

The balanced chemical equation for the oxidation of ${\text{Cl}}^{-}\left(aq\right){\text{ to Cl}}_{\text{2}}\left(g\right)$ by ${\text{PbO}}_{\text{2}}\left(s\right)$ in an acidic solution should be written and whether the reaction occurs spontaneously in the forward direction at [H⁺] = 1.2 M should be explained

Concept introduction:

In an electrochemical cell, there are two electrodes that can be observed.

If oxidation takes place on an electrode, that electrode is called anode. The species in that electrode remove electrons and itself gets oxidized.

If reduction takes place on an electrode, that electrode is called cathode. The species in that electrode absorbs electrons and itself gets reduced.

The electrode potential of cell can be calculated as follows:

$E^0{}_{\text{cell}}=E^0{}_{\text{cathode}} -E^0{}_{\text{anode}}$

Nernst equation for a cell can be represented as follows:

${\text{E}}_{cell}={\text{E}}^0{}_{cell}-\frac{0.0592\text{ V}}{\text{z}}\text{ log Q}$

Here,

z = number of moles of electrons transferred in the cell and Q is ratio of concentration of products to reactant in a cell.

If E _cell is positive, a reaction occurs spontaneously in the forward direction for the stated conditions.

If E _cell is negative, the reaction occurs spontaneously in the reverse direction for the stated conditions.

If the E _cell = 0 reaction is at equilibrium for the stated conditions.

Interpretation Introduction

(c)

Interpretation:

The balanced chemical equation for the oxidation of ${\text{Cl}}^{-}\left(aq\right){\text{ to Cl}}_{\text{2}}\left(g\right)$ by ${\text{PbO}}_{\text{2}}\left(s\right)$ in an acidic solution should be written and whether the reaction occurs spontaneously in the forward direction at pH = 4.25 should be explained

Concept introduction:

From pH of a solution, the concentration of hydrogen ion can be calculated as follows:

$\text{pH}=-\log \left[{\text{H}}^{+}\right]$

Here, $\left[{\text{H}}^{+}\right]$ is hydrogen ion concentration in the solution.

In an electrochemical cell, there are two electrodes that can be observed.

If oxidation takes place on an electrode, that electrode is called anode. The species in that electrode remove electrons and itself gets oxidized.

If reduction takes place on an electrode, that electrode is called cathode. The species in that electrode absorbs electrons and itself gets reduced.

The electrode potential of cell can be calculated as follows:

$E^0{}_{\text{cell}}=E^0{}_{\text{cathode}} -E^0{}_{\text{anode}}$

Nernst equation for a cell can be represented as follows:

${\text{E}}_{cell}={\text{E}}^0{}_{cell}-\frac{0.0592\text{ V}}{\text{z}}\text{ log Q}$

Here,

z = number of moles of electrons transferred in the cell and Q is ratio of concentration of products to reactant in a cell.

If E _cell is positive, a reaction occurs spontaneously in the forward direction for the stated conditions.

If E _cell is negative, the reaction occurs spontaneously in the reverse direction for the stated conditions.

If the E _cell = 0 reaction is at equilibrium for the stated conditions.