Which of the following reactions may occur at the anode of the iron hull? — Electrochemistry Chemistry Question

💡 Solution & Explanation

**Step 1: Recall which reaction type occurs at the anode.** In electrochemical corrosion, the anode is the site of **oxidation** (loss of electrons). The cathode is the site of reduction. **Step 2: Identify the species undergoing oxidation.** The iron hull is the metal being corroded. At the anode, iron atoms lose electrons and dissolve: $$\ce{Fe(s) -> Fe^{2+}(aq) + 2e-}$$ **Step 3: Evaluate each option.** - **(A)** $\ce{Fe^{2+}(aq) -> Fe^{3+}(aq) + e^-}$: This is an oxidation reaction but involves $\text{Fe}^{2+}$ in solution, not the solid hull. While this can occur as a secondary process, the primary anodic dissolution is iron metal to Fe²⁺. - **(B)** $\ce{Fe(s) -> Fe^{2+}(aq) + 2e^-}$: This is the **primary anode reaction** — the iron hull dissolves oxidatively. ✓ - **(C)** $\ce{O2(g) + 4H3O^+(aq) + 4e^- -> 6H2O(l)}$: This is the **cathode** (reduction) reaction — wrong electrode. - **(D)** $\ce{2H2O(l) -> 2OH^-(aq) + H2(g) + 2e^-}$: This is also an oxidation reaction but occurs in strongly basic conditions, not relevant here; besides, the hull anode dissolves iron, not water. $$\boxed{\text{Answer: B — } \ce{Fe(s) -> Fe^{2+}(aq) + 2e^-}}$$