Alcohols Phenols and EthersmediumMCQ MULTIPLE

See imageAlcohols Phenols and Ethers Chemistry Question

Question

See image

Chemistry diagram for: See image
Answer: A,B,F

💡 Solution & Explanation

Step 1: Identify the target molecule. 1-Phenyl-2-propanol has the structure PhCH2-CH(OH)-CH3, i.e., a phenyl group at C1, a hydroxyl at C2, and a methyl at C3. The carbon skeleton is: Ph-CH2-C(OH)(H)-CH3. Step 2: Evaluate each option. Option A: Benzyl Grignard reagent is PhCH2MgBr. Addition to acetaldehyde (CH3CHO) gives PhCH2-CH(OH)-CH3 after protonation. This is exactly 1-phenyl-2-propanol. CORRECT. Option B: Phenyl lithium (PhLi) adds to propylene oxide (methyloxirane, an epoxide with structure CH3-CH(-O-)CH2). Organolithium reagents open epoxides at the less hindered carbon (SN2). Propylene oxide is CH3-CH-O-CH2 (the methyl-bearing carbon is C2, the terminal CH2 is C1). Attack at the less hindered C1 (the CH2 end) gives Ph-CH2-CH(OH)-CH3, which is 1-phenyl-2-propanol. CORRECT. Option C: Phenyl Grignard (PhMgBr) plus acetone (CH3COCH3) gives Ph-C(OH)(CH3)2, which is 2-methyl-1-phenyl-2-propanol (a tertiary alcohol, specifically 2-phenyl-2-propanol). This is NOT 1-phenyl-2-propanol. INCORRECT. Option D: Acid-catalyzed hydration of 2-phenyl-1-propene (Ph-C(CH3)=CH2) follows Markovnikov's rule, placing OH on the more substituted carbon (C2, which bears the phenyl and methyl), giving Ph-C(OH)(CH3)-CH3, i.e., 2-phenyl-2-propanol (a tertiary alcohol). This is NOT 1-phenyl-2-propanol. INCORRECT. Option E: Methyl Grignard (CH3MgBr) plus acetophenone (Ph-CO-CH3) gives Ph-C(OH)(CH3)-CH3, which is 2-phenyl-2-propanol (tertiary). This is NOT 1-phenyl-2-propanol. INCORRECT. Option F: Methyl Grignard (CH3MgBr) plus phenylacetaldehyde (PhCH2CHO) gives PhCH2-CH(OH)-CH3 after protonation. This is exactly 1-phenyl-2-propanol. CORRECT. Step 3: Options A, B, and F all produce 1-phenyl-2-propanol; C, D, and E do not. Therefore, the correct answer is A,B,F.

💬
Still have doubts about this question?
Send it to our AI chemistry tutor on WhatsApp — gets answered in minutes
Ask on WhatsApp →

Practice 22,000+ questions like this

AI-adaptive practice, video lectures, and full JEE Advanced Chemistry content — all in one place.

JEE Advanced · JEE Mains · NEET · IChO · AP Chemistry