NEETChemistryGeneral Organic Chemistry
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): tert-Butyl carbocation is highly stable compared to methyl carbocation. Reason (R): Methyl groups cannot participate in the resonance (mesomeric) effect as they lack bonds or lone pairs of electrons. In the light of the above statements, choose the most appropriate answer from the options given bel
Options
- ABoth (A) and (R) are correct and (R) is the correct explanation of (A)
- BBoth (A) and (R) are correct but (R) is not the correct explanation of (A)
- C(A) is correct but (R) is not correct
- D(A) is not correct but (R) is correct
Correct answer
B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
Step-by-step solution
Assertion (A) is correct: The tert-butyl carbocation, (CH₃)₃C⁺ , is a tertiary carbocation and is highly stable compared to the methyl carbocation, CH₃⁺ . Reason (R) is correct: The resonance (mesomeric) effect involves the delocalization of electrons or lone pairs. Methyl groups ( -CH₃ ) only have bonds and lack bonds or lone pairs, so they cannot participate in resonance. However, (R) is not the correct explanation of (A). The correct explanation for the high stability of the tert-butyl carbocation is that the th