See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Concept: Williamson Ether Synthesis involves the reaction of an alkoxide ion with a primary alkyl halide via SN2 mechanism to form an ether. The best results are obtained when the alkyl halide is primary (unhindered) and the alkoxide is used as the nucleophile. Step 1 - Identify the target molecule: Phenyl n-propyl ether is Ph-O-CH2CH2CH3, an ether with a phenoxy group and an n-propyl chain. Step 2 - Analyze option (a): Phenol is treated with Na metal to form sodium phenoxide (PhO⁻Na⁺), a strong nucleophile/base. This phenoxide then reacts with n-propyl bromide (CH3CH2CH2Br), which is a primary alkyl halide, via SN2. Primary alkyl halides are ideal for SN2 because there is minimal steric hindrance and elimination (E2) is not a competing pathway. This gives Ph-O-CH2CH2CH3, the desired product, in good yield. Step 3 - Analyze option (b): 1-Propanol is treated with Na metal to form sodium n-propoxide (CH3CH2CH2O⁻Na⁺). This alkoxide then reacts with bromobenzene (Ph-Br). Bromobenzene is an aryl halide, which does NOT undergo SN2 reactions under normal conditions because the sp2 carbon is not susceptible to backside attack and the C-Br bond is strengthened by resonance with the ring. This reaction would not produce the ether under these conditions. Step 4 - Conclusion: Option (a) uses a phenoxide (good nucleophile) attacking a primary alkyl halide (good electrophile for SN2), which is the correct application of Williamson Ether Synthesis. Option (b) attempts SN2 on an aryl halide, which fails under normal conditions. Therefore, the correct answer is A.