Let's solve the problem step by step: --- ## **Step 1: Analyze the Target Molecule** The **target molecule** is **phenol** (benzene ring with an -OH group). --- ## **Step 2: Analyze the Starting Material** The **starting material** is **benzene**. --- ## **Step 3: List the Available Reagents** - A. LiAlH₄ - B. H₂, Pd/C - C. Br₂, FeBr₃ - D. HNO₃, H₂SO₄ - E. NaNO₂, HCl - F. H₃O⁺, heat - G. CH₃CH₂Cl/AlCl₃ - H. POCl₃/Pyridine --- ## **Step 4: Determine the Reaction Sequence** To convert benzene to phenol, a classic route is: 1. **Nitration:** Benzene → Nitrobenzene - Reagents: D. HNO₃, H₂SO₄ 2. **Reduction:** Nitrobenzene → Aniline - Reagents: B. H₂, Pd/C 3. **Diazotization:** Aniline → Benzenediazonium salt - Reagents: E. NaNO₂, HCl 4. **Hydrolysis of Diazonium Salt:** Benzenediazonium salt → Phenol - Reagents: F. H₃O⁺, heat --- ## **Step 5: Write the Sequence** Based on the steps above, select the correct order of reagents: | Step | Reagent Letter | Reagent Name | |------|----------------|--------------------------| | 1 | D | HNO₃, H₂SO₄ | | 2 | B | H₂, Pd/C | | 3 | E | NaNO₂, HCl | | 4 | F | H₃O⁺, heat | --- ## **Step 6: Final Answer** **The correct sequence of reagents is:** **D → B → E → F** ### **Explanation of Each Step** 1. **Nitration (D):** Benzene reacts with nitric acid and sulfuric acid to give nitrobenzene. 2. **Reduction (B):** Nitrobenzene is reduced with hydrogen and palladium/carbon to give aniline. 3. **Diazotization (E):** Aniline reacts with sodium nitrite and hydrochloric acid to give benzenediazonium chloride. 4. **Hydrolysis (F):** The diazonium salt is hydrolyzed with aqueous acid and heat to give phenol. --- ### **Summary Table** | Step | Reagent | Purpose | |------|-----------------|--------------------------| | 1 | HNO₃, H₂SO₄ | Nitration | | 2 | H₂, Pd/C | Reduction | | 3 | NaNO₂, HCl | Diazotization | | 4 | H₃O⁺, heat | Hydrolysis to phenol | --- **Final Answer:** > **D, B, E, F** Let me know if you need further clarification on any step!