AIIMS 2018 Chemistry Reaction Mechanisms MCQ Question

Option C is correct because it represents the most stable carbocation, which is typically a tertiary carbocation. Tertiary carbocations benefit from both hyperconjugation and +I (inductive) effects from surrounding alkyl groups, enhancing their stability and thus increasing the rate of the SN₁ reaction.

In contrast, options A (primary carbocation) and B (secondary carbocation) are less stable due to fewer alkyl groups providing stabilizing effects. Option D may represent a resonance-stabilized carbocation, but if it is not as stable as the tertiary carbocation in option C, it will not favor the SN₁ pathway as effectively. Understanding carbocation stability is crucial for predicting reaction mechanisms in organic chemistry.