Which half-equation represents the oxidation of hydrogen in a hydrogen fuel cell?

The chosen half-equation, which shows the oxidation of hydrogen in a hydrogen fuel cell as H2 → 2H+ + 2e-, is correct because it accurately represents the process of hydrogen being oxidized. In this reaction, molecular hydrogen (H2) loses electrons, which is the defining characteristic of oxidation. The formation of protons (H+) and electrons (e-) corresponds to the oxidation half-reaction occurring at the anode of a hydrogen fuel cell.

In a hydrogen fuel cell, hydrogen gas serves as the fuel. When it is introduced to the anode of the fuel cell, it undergoes oxidation, releasing electrons and generating protons. The electrons then flow through an external circuit, which is utilized to generate electrical power, while the protons traverse through the electrolyte to the cathode side of the cell, where they will participate in a reduction reaction with oxygen.

The other representations do not describe the oxidation of hydrogen in a fuel cell context. They either involve reduction processes or depict reactions that do not occur specifically at the anode during hydrogen oxidation. Understanding this oxidation reaction is key to grasping how hydrogen fuel cells operate and the electrochemical processes involved.