Chapter 8, Problem 13Q

During the conversion of O₂(g) to H₂O(l) in a fuel cell, the following half-reaction takes place.

$\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.{\text{O}}_2(g)+2{\text{H}}^{+}(aq)+2e^{-}\to {\text{H}}_2\text{O}(l)$

Does this half-reaction represent an example of oxidation or reduction? Explain.