See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Oxymercuration of alkenes with Hg(OAc)2 in alcohol (EtOH) solvent proceeds via electrophilic addition following Markovnikov's rule. The mercury electrophile and the nucleophile (ethanol) add across the double bond in an anti (trans) addition manner. Step 1 - Identify the alkene: The starting material is 2-methylbut-2-ene, CH3-C(CH3)=CH-CH3. The double bond is between C2 (bearing two methyl groups) and C3. Step 2 - Mechanism of oxymercuration in alcohol: Hg(OAc)2 acts as an electrophile. It forms a mercurinium ion intermediate bridging the double bond. The nucleophile (EtOH) then attacks the more substituted carbon (Markovnikov selectivity) in an anti fashion. Wait - actually in standard oxymercuration, the nucleophile attacks the MORE substituted carbon. Here C2 is more substituted (tertiary) than C3 (secondary). Step 3 - Regioselectivity: The nucleophile (EtOH/OEt) attacks the more substituted carbon (C2, the tertiary carbon bearing the methyl group), while -HgOAc ends up on the less substituted carbon (C3, the secondary carbon). This gives: CH3-C(CH3)(OEt)-CH(HgOAc)-CH3. Step 4 - Product identification: The OEt group is on C2 (the more substituted/Markovnikov carbon) and HgOAc is on C3. This matches option (b): CH3-C(CH3)(OEt)-CH(HgOAc)-CH3. Why other options fail: - Option (a): Has HgOAc on C2 and OEt on C3 - this is anti-Markovnikov placement of OEt, incorrect. - Option (c): Has OH instead of OEt on C2 - wrong nucleophile (solvent is EtOH, not water). - Option (d): Has HgOAc on C2 and OH on C3 - wrong nucleophile and wrong regiochemistry. Therefore, the correct answer is B.