MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The given reactant is 3-methylhex-3-ene. The addition of HI to an alkene is an electrophilic addition reaction that proceeds via the formation of a carbocation intermediate. First, the electrophile H^+ attacks the double bond. This can result in two possible carbocations: 1. Protonation at C-4 yields a tertiary carbocation at C-3. 2. Protonation at C-3 yields a secondary carbocation at C-4. Since a tertiary carbocation is significantly more stable than a secondary carbocation due to greater hyperconjugation and inductive effects, the reaction proceeds predominantly through the tertiary carbocation at C-3. Finally, the nucleophile I^- attacks this more stable tertiary carbocation, resulting in the iodine atom attaching to C-3. The major product formed is 3-iodo-3-methylhexane. Answer: 3 - iodo - 3 - methylhexane