Question

In a ${{\text{H}}_{\text{2}}}-{{\text{O}}_{2}}$ fuel cell, combustion of hydrogen occurs to:
A.Remove adsorbed oxygen from electrode surface
B.Create potential difference between the two electrodes
C.Produce high purity water
D.Generate heat

Answer 1

Hint:A fuel cell uses the chemical energy of hydrogen and another fuel to cleanly and efficiently produce electricity. These cells work like batteries but they do not need recharging or run down.

Complete answer:
In the ${{\text{H}}_{\text{2}}}-{{\text{O}}_{2}}$ fuel cell, the chemical energy of the fuel which is often hydrogen and an oxidising agent which is often oxygen, is converted to electrical energy. These are different from the batteries in the regard that most of the batteries require a continuous source of fuel.
There are different variations of the fuel cells but they all consist of an anode, a cathode, and an electrolyte. Two chemical reactions occur at the interfaces of the three segments. The net result of the two reactions is that fuel is consumed, either water, or carbon dioxide is formed and an electric current is created, which can be used to power electrical devices.
Hence in a ${{\text{H}}_{\text{2}}}-{{\text{O}}_{2}}$ fuel cell, combustion of hydrogen occurs to “Create potential difference between the two electrodes”.

So, the correct option is B.
Note:
There are different catalysts that are used in the ${{\text{H}}_{\text{2}}}-{{\text{O}}_{2}}$ fuel cell, the anode catalyst usually being fine platinum powder and the catalyst at the cathode being nickel that converts ions waste chemicals, with water being the most common type of waste. The electrolyte substance is generally potassium hydroxide, carbonate salts, and phosphoric acid.