In the electrochemical cell based on the reaction Zn(s) + Cu^{2+}(aq) → Zn^{2+}(aq) + Cu(s), which of the following correctly lists the half-reactions occurring at the anode and cathode?

• A. Anode: Cu^{2+}(aq) + 2e^- → Cu(s); Cathode: Zn(s) → Zn^{2+}(aq) + 2e^-
• B. Anode: Zn(s) → Zn^{2+}(aq) + 2e^-; Cathode: Cu^{2+}(aq) + 2e^- → Cu(s)
• C. Anode: Zn^{2+}(aq) + 2e^- → Zn(s); Cathode: Cu(s) → Cu^{2+}(aq) + 2e^-
• D. Anode: Cu(s) → Cu^{2+}(aq) + 2e^-; Cathode: Zn^{2+}(aq) + 2e^- → Zn(s)

Answer: (B)

Verified step by step guidance

1. Identify the overall redox reaction: Zn(s) + Cu^{2+}(aq) → Zn^{2+}(aq) + Cu(s). This shows zinc metal reacting with copper ions to form zinc ions and copper metal.
2. Determine which species is oxidized and which is reduced by comparing oxidation states: Zn goes from 0 to +2 (oxidation), Cu goes from +2 to 0 (reduction).
3. Recall that oxidation occurs at the anode and involves loss of electrons, so the anode half-reaction is Zn(s) → Zn^{2+}(aq) + 2e^-.
4. Recall that reduction occurs at the cathode and involves gain of electrons, so the cathode half-reaction is Cu^{2+}(aq) + 2e^- → Cu(s).
5. Match these half-reactions to the options given to identify the correct listing of anode and cathode half-reactions.