Chemistry - Hydrocarbon Question with Solution | TestHub

The reactions shown are hydration reactions that add H and OH across the double bond. The first two reactions (dil. H₂SO₄, and oxymercuration-demercuration) follow Markovnikov's rule, where the OH group attaches to the more substituted carbon. The third reaction (hydroboration-oxidation) follows anti-Markovnikov's rule, where the OH group attaches to the less substituted carbon. For products P, Q, and R to be the same constitutional isomer, the alkene must be symmetrical. For Trans-2-Butene and Cis-2-Butene (CH₃CH=CHCH₃), the double bond carbons are equally substituted. Both Markovnikov and anti-Markovnikov additions yield the same major constitutional product: 2-butanol (CH₃CH(OH)CH₂CH₃). The products are stereoisomers of each other (racemic mixtures), but are the same constitutional isomer. For 1-Butene and Isobutene, the double bond carbons are not equally substituted, leading to different major constitutional products for Markovnikov vs. anti-Markovnikov additions.