Question

Given below are two statements:
Statement (I) : S$_N$2 reactions are 'stereospecific', indicating that they result in the formation only one stereo-isomers as the product.
Statement (II) : S$_N$1 reactions generally result in formation of product as racemic mixtures.
In the light of the above statements, choose the correct answer from the options given below :

• A. Statement I is true but Statement II is false
• B. Statement I is false but Statement II is true
• C. Both Statement I and Statement II is true
• D. Both Statement I and Statement II is false

Answer 1

The Correct Option is C

To assess the provided statements concerning S_N2 and S_N1 reactions, we will examine their fundamental principles:

1. Statement (I): S_N2 reactions are characterized as 'stereospecific,' meaning only a single stereoisomer is produced.

Explanation: S_N2 reactions proceed through a single, bimolecular step involving nucleophilic substitution. The nucleophile's attack occurs on the carbon atom from the opposite side of the departing leaving group, resulting in an inversion of stereochemical configuration at the chiral center (Walden inversion). Consequently, the reaction yields a specific stereoisomer.

1. Statement (II): S_N1 reactions typically yield racemic mixtures of products.

Explanation: S_N1 reactions involve a two-step process initiated by the formation of a carbocation intermediate. Due to the planar nature of the carbocation, the nucleophile can attack from either face, leading to the generation of both enantiomers in equal amounts. This results in the formation of a racemic mixture.

Consequently, both Statement I and Statement II accurately reflect the established mechanisms of S_N2 and S_N1 reactions. Therefore, the correct conclusion is:

Both Statement I and Statement II are true