See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

**Identifying the Most Acidic Hydrogen** The most acidic hydrogen in a carbonyl compound is the α-hydrogen (attached to the carbon adjacent to the carbonyl group), because: - The carbonyl carbon is electron-withdrawing - Deprotonation forms a resonance-stabilized enolate ion **Comparing the Options:** **(A) 3-hexanone:** $CH_3{-}CO{-}CH_2{-}CH_2{-}CH_2{-}CH_3$ - Has one carbonyl group; α-hydrogens are on adjacent carbons - Moderate acidity **(B) 2,4-hexanedione:** $CH_3{-}CO{-}CH_2{-}CO{-}CH_2{-}CH_3$ - Two carbonyl groups with one $CH_2$ between them (β-dicarbonyl) - The central $CH_2$ is flanked by **two carbonyl groups** - Both carbonyls withdraw electrons and stabilize the enolate - Forms a particularly stable resonance structure (conjugated system) **(C) 2,5-hexanedione:** $CH_3{-}CO{-}CH_2{-}CH_2{-}CO{-}CH_3$ - Two carbonyls separated by two carbons - Less stabilization of the deprotonated anion **(D) 2,3-hexanedione:** $CH_3{-}CO{-}CO{-}CH_2{-}CH_2{-}CH_3$ - Adjacent carbonyls (no α-hydrogen between them) - No synergistic effect **Answer: (B)** has the most acidic hydrogen because the central $CH_2$ is α to *both* carbonyl groups, providing maximum enolate stabilization through dual electron-withdrawal.