When exactly 2-bromobutane undergoes dehydrohalogenation with alcoholic , what is the total maximum — Reaction Mechanism Chemistry Question
Question
When exactly 2-bromobutane undergoes $E2$ dehydrohalogenation with alcoholic $KOH$, what is the total maximum number of distinct alkene products formed (counting all distinct structural isomers and unique stereoisomers)?
💡 Solution & Explanation
The elimination of $HBr$ from 2-bromobutane can occur between C1 and C2, yielding 1-butene. Alternatively, elimination between C2 and C3 yields 2-butene. Because 2-butene has two non-identical groups on each double-bonded carbon, it exhibits geometric isomerism, forming both cis-2-butene and trans-2-butene. Summing the unique products gives exactly 3 variants: 1-butene, cis-2-butene, and trans-2-butene.