Chapter 19, Problem 19.30P

Interpretation Introduction

(a)

Interpretation:

The value of standard potential for the cell reaction needs to be determined in the PEM fuel cell.

Concept introduction:

In the cell, oxidation takes place at anode and reduction at cathode. The oxidation of aluminum and reduction of oxygen gas takes place. The overall cell reaction is sum of reaction at cathode and anode.

Interpretation Introduction

(b)

Interpretation:

The cell voltage needs to be determined if partial pressure of hydrogen and oxygen gas is 6 atm and 0.20 atm respectively.

Concept introduction:

The Nernst equation of a cell is used to determine the electrode potential of the cell using the standard cell potential

The reaction queotient of the cell is ratio of concentration of products to reactants in the cell reaction.

The Nernst equation can be represented as follows:

$E=E^o-\frac{2.303RT}{nF}\log Q$

Here, $E$ is cell potential, $E^o$ is standard cell potential, R is Universal gas constant, n is number of electrons involved in cell reaction, T is temperature, F is Faraday’s constant and Q us reaction quotient.