AIIMS 2018 Chemistry Friedel-Crafts Alkylation Assertion Reason Question
Assertion: The carbocation is less stable than .
Reason: In case of , the strongly electron-withdrawing group intensifies the +ve charge but in case of , the lone pairs of electrons on each of the three -atoms overlap with the empty -orbital of the carbocation carbon thereby dispersing the +ve charge.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Correct Answer
Detailed Explanation
Option A is correct because the reaction involving isopropyl benzene (also known as cumene) demonstrates the rearrangement of a primary carbocation to a more stable secondary carbocation, which facilitates the formation of the product. This mechanism highlights the principle of carbocation stability, where secondary carbocations are favored over primary ones due to their greater hyperconjugation and inductive effects. Other options are not applicable as they do not provide alternative assertions or reasons to evaluate. Understanding this rearrangement is crucial for grasping the fundamentals of organic reaction mechanisms and carbocation stability.
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