See image — Alcohols Phenols and Ethers Chemistry Question

💡 Solution & Explanation

Concept: This reaction involves transesterification / ester exchange under acidic conditions with excess acetic acid. Step 1: Identify the starting ester. Ethyl 2-chloro-2-phenylacetate is Ph-CH(Cl)-C(=O)-OCH2CH3 (an ethyl ester). It reacts with acetic acid (CH3COOH, 7 moles excess) under HCl catalyst with heat. Step 2: Mechanism - Under acidic conditions (HCl catalyst) with excess acetic acid acting as both reagent and solvent, an esterification/transesterification equilibrium is established. The ethoxy group (-OEt) of the ester can be exchanged. However, the key reaction here is: acetic acid reacts with the ethyl ester in a transesterification process. The acetic acid (nucleophilic attack at the ester carbonyl) exchanges the -OEt group, releasing ethanol, which then reacts with acetic acid to form ethyl acetate. But looking more carefully: acetic acid provides -OH, and the ethyl ester undergoes acid-catalyzed hydrolysis-like substitution. Actually, in the presence of excess acetic acid and HCl at elevated temperature, the reaction proceeds via: the -OCH2CH3 group is displaced. The carboxylic acid (acetic acid) attacks the ester carbonyl, leading to exchange. The ethanol released reacts with acetic acid to give CH3-C(=O)-OCH2CH3 (ethyl acetate). But wait - product B contains chlorine per the problem statement. Let me re-read: '(B) contains chlorine.' So B is the chlorine-containing product. Step 3: Re-examining. Product (A) does not contain chlorine (it's the acetic acid-derived product), and product (B) contains chlorine (it retains the Ph-CH(Cl) group). In option (a): A = Ph-CH(Cl)-C(=O)-OH and B = CH3-C(=O)-OCH2CH3. Here A contains chlorine and B does not. But the problem says B contains chlorine. So actually let me reconsider which is A and which is B. Step 4: The problem states (B) contains chlorine. In option (a): A = Ph-CH(Cl)-COOH (contains Cl) and B = CH3COOEt (no Cl). This seems reversed from the label. But the answer is given as (a). Under the reaction conditions (excess acetic acid, HCl, heat), the ethyl ester undergoes acid-catalyzed exchange: the ester reacts with CH3COOH. Under forcing acidic conditions, the ester bond is cleaved to give the free acid Ph-CH(Cl)-COOH (product A) and ethanol, which esterifies with acetic acid to give ethyl acetate CH3-C(=O)-OCH2CH3 (product B). Product B = CH3COOEt does not contain chlorine as written, but reviewing the image description again - the problem labels say '(B) contains chlorine' referring to B in options context. Actually re-reading: the arrow leads to (A) + (B) and the note '(contains chlorine)' modifies (B). In option (a), B = CH3-C(=O)-OCH2CH3 which has no chlorine, and A = Ph-CH(Cl)-COOH which has chlorine. This is a mislabeling or the '(contains chlorine)' note refers to (A) not (B), or the labeling in the answer key assigns the chlorine compound as A. Given the answer is (a), A = Ph-CH(Cl)-C(=O)-OH (2-chloro-2-phenylacetic acid, from hydrolysis of the ethyl ester by acetic acid acting as a water equivalent under these conditions) and B = CH3-C(=O)-OCH2CH3 (ethyl acetate, from the released ethanol reacting with excess acetic acid). The reaction is essentially acid-catalyzed hydrolysis/transesterification where acetic acid cleaves the ester to give the carboxylic acid and ethyl acetate. Step 5: Why other options fail: - (b): B = CH3COOCH3 implies methanol release, which is not possible from ethyl ester. - (c): A = Ph-CH(Cl)-COOEt means the ester is unchanged, which contradicts reaction occurring. - (d): Implies C-Cl bond cleavage and loss of the ester group entirely, not consistent with mild esterification conditions. Therefore, the correct answer is A.