When molten NaCl is electrolyzed, which products are formed at the cathode and anode, respectively?

• A. Cathode: NaCl; Anode: Na
• B. Cathode: Cl_2; Anode: Na
• C. Cathode: H_2; Anode: O_2
• D. Cathode: Na; Anode: Cl_2

Answer: (D)

Verified step by step guidance

1. Identify the species present in molten NaCl. Since it is molten, NaCl dissociates into Na⁺ and Cl⁻ ions, with no water present to participate in the reaction.
2. At the cathode (the site of reduction), cations gain electrons. Determine which cation will be reduced: Na⁺ or any other possible species. Here, Na⁺ ions will gain electrons to form sodium metal (Na). The half-reaction is: \(\mathrm{Na^{+} + e^{-} \rightarrow Na}\).
3. At the anode (the site of oxidation), anions lose electrons. Determine which anion will be oxidized: Cl⁻ or any other species. Here, Cl⁻ ions lose electrons to form chlorine gas (Cl₂). The half-reaction is: \(\mathrm{2Cl^{-} \rightarrow Cl_2 + 2e^{-}}\).
4. Combine the half-reactions to understand the overall process: sodium metal forms at the cathode, and chlorine gas forms at the anode.
5. Conclude that the products formed during the electrolysis of molten NaCl are sodium metal at the cathode and chlorine gas at the anode.