See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Concept: 1-Phenylethanol (C6H5-CH(OH)-CH3) is a secondary alcohol with a phenyl group and a methyl group attached to the carbinol carbon. It can be synthesized by reacting benzaldehyde (C6H5-CHO) with a Grignard reagent. The nucleophilic addition of a Grignard reagent to benzaldehyde, followed by hydrolysis, gives a secondary alcohol. Step 1: Identify the target molecule. 1-Phenylethanol is C6H5-CH(OH)-CH3. The carbon bearing the OH comes from benzaldehyde, and the CH3 group must be added as a nucleophile. Step 2: Determine which Grignard reagent is needed. To add a methyl group to benzaldehyde (C6H5-CHO), we need methylmagnesium iodide (CH3MgI), which is the Grignard reagent. Step 3: Identify how CH3MgI is prepared. The Grignard reagent CH3MgI is prepared by the reaction of CH3I (methyl iodide) with Mg metal in dry ether. This corresponds to option (a). Step 4: The reaction sequence is: - CH3I + Mg (dry ether) → CH3MgI (methylmagnesium iodide) - CH3MgI + C6H5-CHO → C6H5-CH(OMgI)-CH3 - Hydrolysis → C6H5-CH(OH)-CH3 (1-phenylethanol) Why other options fail: - Option (b): C2H5I + Mg gives ethylmagnesium iodide (C2H5MgI). Reaction with benzaldehyde would give 1-phenyl-1-propanol, not 1-phenylethanol. - Option (c): CH3Br + AlCl3 is a Friedel-Crafts alkylation reagent system, not a Grignard reagent preparation. It would not produce a nucleophile capable of adding to benzaldehyde in this context. - Option (d): CH3OH + ZnCl2 does not produce a useful organometallic reagent for this synthesis. Therefore, the correct answer is A.