Question

In a hydrogen - oxygen fuel cell, combustion of hydrogen occurs to :

• A. Produce high purity water
• B. Create potential difference between the two electrodes
• C. Generate heat
• D. Remove adsorbed oxygen from electrode surfaces

Answer 1

Answer: (C)

Explanation:
In a Hydrogen-oxygen fuel cell, the oxygen is reduced at the cathode and the hydrogen is oxidized at the anode.

Adding these two reactions leads to the combustion reaction of hydrogen, which generates tremendous heat.
The direct combustion of hydrogen is uncontrollable, but via an electrochemical cell, this can be controlled to some extent.
$H_2\to 2H^{+}+2e^{-}$(at anode).
$O_2+2H_{2}O+4e^{-}\to 4O{H}^{-}$(at cathode)
$2H_2+O_2\to 2H_{2}O$ ( Overall )