Chemistry - STRUCTURAL ISOMERISM Question with Solution | TestHub

Trace base moves protons through an enediol : Ph-CH(OH)-CHO loses the alpha proton (the carbinol C-H) to give the enediol Ph-C(OH)=CH-OH, which re-ketonises at the other carbon to give Ph-CO-CH₂-OH (phenacyl alcohol, 2-hydroxy-1-phenylethanone) - an isomer of (A). The other choices cannot result from simple proton shifts : (A) and (B) require oxidation-state/ connectivity changes of the carbon framework and (D) requires moving the phenyl group from carbon to oxygen. Hence (B) is Ph-CO-CH₂-OH, option (C).