Chapter 19, Problem 19.36QP

Interpretation Introduction

Interpretation:

The advantages and disadvantages of fuel cells over conventional power generation methods has to be discussed.

Concept introduction:

In conventional methods electricity was generated in three steps, first heat was generated by combustion of fossil fuels or from nuclear energy, in second step heat energy was utilized to change water into stream, finally steam was used to drives the generator. Since the combustion reaction is a redox reaction it can be conveniently carried out in an electrochemical manner, such a setup is called fuel cell, hydrogen-oxygen fuel cell is the representative example of fuel cell. It consists of an electrolyte solution, such as a potassium hydroxide solution and two inert electrodes. Hydrogen and oxygen gases were bubbled through the anode and cathode where the reaction takes place as follows,

$\begin{array}{l}\text{Anode (Oxidation)}{\text{2H}}_{\text{2}}{}_{\text{(g)}}{\text{+4OH}}^{\text{-}}{}_{\text{(aq)}}\stackrel{}{\to }{\text{4H}}_{\text{2}}{\text{O}}_{\text{(l)}}{\text{+4e}}^{\text{-}}\\ \text{Cathode (Reduction)}{\text{O}}_{\text{2}}{}_{\text{(g)}}{\text{+ 2H}}_{\text{2}}{\text{O}}_{\text{(l)}}{\text{+4e}}^{\text{-}}\stackrel{}{\to }{\text{4OH}}^{\text{-}}{}_{\text{(aq)}}\\ \text{Overall}\text{Reaction}{\text{2H}}_{\text{2}}{}_{\text{(g)}}{\text{+O}}_{\text{2}}{}_{\text{(g)}}\stackrel{}{\to }{\text{2H}}_{\text{2}}{\text{O}}_{\text{(l)}}\end{array}$

To highlight: The advantages of fuels cells over the conventional power generation methods.