Discuss the working of hydrogen-oxygen fuel cell. What are the advantages of using this fuel cell?

One of the most successful fuel cells uses the reaction of hydrogen with oxygen to form water. The cell was used for providing electrical power in the Apollo space programme. The water vapours produced during the reaction were condensed and added to the drinking water supply for the astronauts. In the cell, hydrogen and oxygen are bubbled through porous carbon electrodes into concentrated aqueous sodium hydroxide solution. Catalysts like finely divided platinum or palladium metal are incorporated into the electrodes for increasing the rate of electrode reactions. The electrode reactions are given below

Cathode: O2 (g) + 2H₂O(l) + 4e^–→ 4OH^– (aq)

Anode: 2H₂ (g) + 4OH^– (aq) → 4H₂O(l) + 4e^–

 Overall reaction being: 2H₂ (g) + O₂ (g) → 2H₂O(l )

The cell runs continuously as long as the reactants are supplied. Fuel cells produce electricity with an efficiency of about 70 % compared