What are fuel cells ? Give example.

Explanation

These are voltaic cell in which the reactants are continuously supplied to the electrodes. These are designed to convert the energy from the combustion of fuel such as `H_(2), CO, CH_(4)` etc. directly into electricla energy.

Reactions: Anode: `2H_(2)(g) + 2OH^(- ) (aq) rarr 2H_(2)O (l) + 2e^(-)`
Cathode : `O_(2) (g) + 2H_(2)O(l) + 4e^(-) rarr 4OH^(-) (aq)`
Overall: `2H_(2) (g) + O_(2) (g) rarr 2H_(2) O (l)`
Voltage : 0.6 to 0.7 voltage of fuel cell
Uses: 1. High efficiency
2. Continuos source of energy
3. Pollution free working.