The (Elimination Unimolecular conjugate Base) mechanism is a specialized pathway. It is most likely — Reaction Mechanism Chemistry Question

💡 Solution & Explanation

The $E1cB$ mechanism proceeds via a carbanion intermediate. It strongly requires the $\beta$ -hydrogen to be unusually acidic, which happens when a potent electron-withdrawing group (e.g., carbonyl, nitro) is attached to the $\beta$ -carbon. Furthermore, the leaving group must be exceptionally poor (like $F^-$ or $OH^-$) so that the initial fast deprotonation does not trigger an immediate concerted $E2$ elimination, forcing the leaving group departure into a subsequent slow step.