Consider a galvanic cell in which Al3+ is reduced to elemental aluminum and magnesium metal is oxidized to Mg2+. Write the balanced half-cell reactions that take place at the cathode and at the anode. half-cell reaction at the cathode: half-cell reaction at the anode: 8. Fuel cells are a particular type of electrochemical cell that require a constant source of chemical fuels, or reactants, during operation. One of the most common types of fuel cells is the alkaline fuel cell, which uses hydrogen and oxygen as reactants. What species are formed at the anode of the alkaline fuel cell? O2H2OH+e?OH?H2 What species are formed at the cathode of the alkaline fuel cell? Write the balanced half?reaction that occurs at the anode in a hydrogen–oxygen fuel cell in which an alkaline electrolyte is used. anode half-reaction: Write the balanced half?reaction that occurs at the cathode in a hydrogen–oxygen fuel cell in which an alkaline electrolyte is used. cathode half-reaction: Write the balanced overall cell reaction. overall cell reaction: H2H2OO2H+OH?e? 9.