Question

An $S_{N}2$ reaction of an asymmetric carbon of a compound always gives:

• A. an enantiomer of the substrate
• B. a product with opposite optical rotation
• C. a mixture of diastereomers
• D. a single stereoisomer

Answer 1

The correct option is B a product with opposite optical rotation

$S_{N}2$ reaction at asymmetric carbon means the Nucleophilic substitution through the formation of transition state occurs at the chiral carbon in the compound.

The leaving group is then pushed off the opposite side and the product is formed with inversion of the tetrahedral geometry at the central atom.

Hence, it will have opposite optical rotation.

Option B is correct.