What is a fuel cell? What is the most common type of fuel cell, and what reactions occur at its anode and cathode?
a) A fuel cell is an electrochemical device that converts chemical energy directly into electrical energy. The most common type is the hydrogen-oxygen fuel cell. The anode reaction is 2H2→4H++4e−, and the cathode reaction is O2+4H++4e−→2H2O.