Final answer:
The half-reaction Cr3+ (aq) + 3e- -> Cr(s) is a reduction process, not oxidation, because it involves the gain of electrons by the chromium ion.
Step-by-step explanation:
The given half-reaction Cr^{3+} (aq) + 3e^- \rightarrow Cr(s) represents a reduction process, not oxidation. In this half-reaction, the chromium ion (Cr3+) is gaining three electrons (3e-) to form solid chromium (Cr), which means it is being reduced. In electrochemistry, the species that gains electrons undergoes reduction. Oxidation, on the other hand, is characterized by the loss of electrons.
The oxidation state of chromium is decreasing from +3 to 0 in this reaction, which is a typical sign of a reduction process. As per the electrochemical series, if a species is higher on the series, such as Fe2+, and reacts with a species below it, like Cr, the one higher will act as the oxidant, and the reaction will be spontaneous. Also, oxidation occurs at the anode, while reduction occurs at the cathode in an electrochemical cell.