Optically pure (R)-1-chloro-1-phenylethane, C6H5-CH(CH3)-Cl, is solvolysed in aqueous acetone. The product C6H5-CH(CH3)-OH is found to contain 64% of the product formed with inversion of configuration and 36% formed with retention. The product mixture is

28% enantiomeric excess of the (S) alcohol

64% enantiomeric excess of the (S) alcohol

28% enantiomeric excess of the (R) alcohol

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JEE Main levelSingle correct optionDifficulty 2 of 3o3019

Optically pure (R)-1-chloro-1-phenylethane, $C X_{6} H X_{5} - CH (CH X_{3}) - Cl$ , is solvolysed in aqueous acetone. The product $C X_{6} H X_{5} - CH (CH X_{3}) - OH$ is found to contain 64% of the product formed with inversion of configuration and 36% formed with retention. The product mixture is

A28% enantiomeric excess of the (S) alcohol
B64% enantiomeric excess of the (S) alcohol
C28% enantiomeric excess of the (R) alcohol
Da racemic mixture

Answer: A

The priority order is

Cl

(or

OH

) > phenyl > methyl > H in both chloride and alcohol, so inversion changes the descriptor from (R) to (S). The mixture is 64% (S) and 36% (R) (partial inversion from ion-pair collapse), so the excess is

64 - 36 = 28

% of the (S) alcohol.

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Optically pure (R)-1-chloro-1-phenylethane, CX6​HX5​−CH(CHX3​)−Cl, is solvolysed in aqueous acetone. The product CX6​HX5​−CH(CHX3​)−OH is found to contain 64% of the product formed with inversion of configuration and 36% formed with retention. The product mixture is

Answer: A

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