What reaction occurs at the negative electrode of a hydrogen-oxygen fuel cell?

At the negative electrode of a hydrogen-oxygen fuel cell, known as the anode, hydrogen gas undergoes an oxidation reaction. The correct representation of this reaction is that hydrogen gas reacts with hydroxide ions to produce water and release electrons. The reaction describes the conversion of molecular hydrogen into water while generating electrical energy.

This specific reaction occurs as follows: hydrogen gas combines with hydroxide ions to form water and releases electrons. These electrons flow through an external circuit, providing electrical power, while the water is produced as a byproduct. This mechanism is central to the operation of fuel cells because it demonstrates the conversion of chemical energy into electrical energy.

The other choices represent different processes or locations in the overall fuel cell reaction and do not accurately depict what happens at the negative electrode. Thus, the correct answer emphasizes the oxidation of hydrogen leading to the energy-harvesting function of the fuel cell.