What does hydrogen produce when it reacts with oxygen in the fuel cell?

When hydrogen reacts with oxygen in a fuel cell, the primary product is water. This reaction is a part of the electrochemical processes that take place in the fuel cell, where hydrogen gas undergoes oxidation at the anode and oxygen gas undergoes reduction at the cathode. The overall reaction can be represented by the equation:

2H₂ + O₂ → 2H₂O.

This reaction is highly efficient and clean, as it generates electricity, heat, and water, with water being the only emission from the fuel cell. The formation of carbon dioxide, methane, or hydrogen peroxide does not occur in this process, making water the straightforward and expected product of hydrogen and oxygen interacting in a fuel cell environment.