Question

Consider the following reaction:

The CORRECT statement(s) related to mono-chlorination at carbon-2 position is/are

• A. The reaction proceeds through alkyl radical intermediate
• B. Complete inversion of configuration at carbon-2 takes place
• C. Complete retention of configuration at carbon-2 takes place
• D. An aqueous solution of aspirin (HA) is prepared at pH 7.4. The ratio of concentration of \( \text{A}^- \) and \( \text{HA} \) at equilibrium is ________. (round off to the nearest integer).

Hint:

In reactions involving radicals, products are often formed as a mixture of enantiomers due to the non-stereoselective nature of the radical attack.

Answer 1

The Correct Option is A, D

Step 1: Mechanism of the reaction.
The reaction shown is a photochemical chlorination of an alkene. In this reaction, the chlorine molecule (\( \text{Cl}_2 \)) is dissociated under the influence of light (\( \text{hv} \)) to form chlorine radicals. These radicals then react with the alkene to produce alkyl radicals, which are highly reactive intermediates in the mechanism.
Step 2: Analyzing the options.
- (A) The reaction proceeds through alkyl radical intermediate: This is correct. The photochemical chlorination produces radicals that react to form products.
- (B) Complete inversion of configuration at carbon-2 takes place: This is incorrect. The reaction involves the formation of a radical, which leads to a mixture of products, not inversion.
- (C) Complete retention of configuration at carbon-2 takes place: This is incorrect. The chlorination does not proceed with complete retention of configuration.
- (D) A mixture of enantiomers is formed: This is correct. Since the reaction occurs at a chiral center, a mixture of enantiomers is formed.

Step 3: Conclusion.
The correct answers are (A) and (D), as the reaction proceeds via radical intermediates, and the product is a mixture of enantiomers.