Which of the following compounds does NOT exhibit keto-enol tautomerism?

Step-by-step solution

Keto-enol tautomerism is exhibited by carbonyl compounds that have at least one -hydrogen atom. In CH₃COCH₃ , there are six -hydrogen atoms. In C₆H₅COCH₃ , there are three -hydrogen atoms. In C₆H₅COC₆H₅ (benzophenone), the carbonyl carbon is attached to two phenyl rings. The carbon atoms of the phenyl rings adjacent to the carbonyl group do not have any hydrogen atoms. Since there are no -hydrogen atoms, it does not exhibit keto-enol tautomerism. In CH₃CH₂CHO , there are two -hydrogen atoms. Answer: C₆H₅COC₆H₅