Read the assertion and reason carefully to mark the correct option out...
Optically active 2-iodobutane on treatment with NaI in acetone undergoes racemisation.
Repeated Walden inversions on the reactant and its product eventually gives a racemic mixture.
Read the assertion and reason carefully to mark the correct option out...
Assertion: Optically active 2-iodobutane on treatment with NaI in acetone undergoes racemization.
Reason: Repeated Walden inversions on the reactant and its product eventually gives a racemic mixture.
The correct option is A) If both assertion and reason are true and the reason is the correct explanation of the assertion.
Explanation:
To understand the assertion and reason provided, let's break down the information and analyze it step by step.
Optically active 2-iodobutane:
2-iodobutane is a chiral molecule with a stereocenter, meaning it has two different enantiomers (mirror images) that are non-superimposable. This molecule can rotate the plane of polarized light and is therefore optically active.
Treatment with NaI in acetone:
When 2-iodobutane is treated with NaI (sodium iodide) in acetone, a substitution reaction takes place. The iodide ion (I-) from NaI replaces the leaving group (iodine atom) in 2-iodobutane, resulting in the formation of 2-iodobutane and sodium iodide as the byproduct.
Walden inversion:
Walden inversion refers to the inversion of the configuration at a stereocenter during a nucleophilic substitution reaction. In this case, when the iodide ion attacks the 2-iodobutane, the configuration at the stereocenter is inverted, resulting in the formation of the opposite enantiomer.
Racemization:
Racemization occurs when a chiral compound is converted into a racemic mixture, which contains equal amounts of both enantiomers. In this case, the repeated Walden inversions on the reactant (optically active 2-iodobutane) and its product (generated by the substitution reaction) lead to the formation of a racemic mixture.
Explanation of the reason:
The reason provided in the assertion-reason pair correctly explains why optically active 2-iodobutane undergoes racemization. The repeated Walden inversions during the substitution reaction lead to the formation of both enantiomers, resulting in a racemic mixture.
Therefore, option A is the correct answer as both the assertion and reason are true, and the reason is the correct explanation of the assertion.