Which of the following reactions is NOT an example of an oxidation–reduction (redox) reaction?

• A. 2H2O2(aq) → 2H2O(l) + O2(g)
• B. 2Fe^{3+}(aq) + 2I^-(aq) → 2Fe^{2+}(aq) + I2(s)
• C. Zn(s) + Cu^{2+}(aq) → Zn^{2+}(aq) + Cu(s)
• D. HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)

Answer: (D)

Verified step by step guidance

1. Step 1: Understand what defines an oxidation–reduction (redox) reaction. A redox reaction involves the transfer of electrons between species, resulting in changes in their oxidation states.
2. Step 2: Analyze the first reaction: \$2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)$. Here, oxygen changes its oxidation state, indicating electron transfer, so this is a redox reaction.
3. Step 3: Analyze the second reaction: \$2Fe^{3+}(aq) + 2I^-(aq) \rightarrow 2Fe^{2+}(aq) + I_2(s)$. Iron is reduced from +3 to +2, and iodide is oxidized to iodine, so this is a redox reaction.
4. Step 4: Analyze the third reaction: \(Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s)\). Zinc is oxidized from 0 to +2, and copper is reduced from +2 to 0, so this is a redox reaction.
5. Step 5: Analyze the fourth reaction: \(HCl(aq) + NaOH(aq) \rightarrow NaCl(aq) + H_2O(l)\). This is an acid-base neutralization where no change in oxidation states occurs, so it is NOT a redox reaction.