When an aqueous solution of NaBr is electrolyzed, which product is formed at the anode?

• A. H2
• B. Na
• C. NaOH
• D. Br2

Answer: (D)

Verified step by step guidance

1. Identify the species present in the aqueous NaBr solution: Na\textsuperscript{+}, Br\textsuperscript{-}, H2O molecules, and possibly H\textsuperscript{+} and OH\textsuperscript{-} from water dissociation.
2. Recall that during electrolysis, oxidation occurs at the anode (loss of electrons), and reduction occurs at the cathode (gain of electrons).
3. Determine which species can be oxidized at the anode: Br\textsuperscript{-} ions or water molecules. Compare their standard oxidation potentials to see which is more easily oxidized.
4. Since Br\textsuperscript{-} ions have a lower oxidation potential than water, Br\textsuperscript{-} ions are preferentially oxidized to form Br2 gas at the anode.
5. Conclude that the product formed at the anode during electrolysis of aqueous NaBr is bromine gas (Br2), not H2, Na, or NaOH.