Which of the following compounds is an enol of compound X drawn below?

Question

Quizplus · Accepted Answer

Compound X is a ketone with a carbonyl group (C=O) at the center. An enol is formed when one of the α-hydrogen atoms on the carbon next to the carbonyl group is removed as a proton, creating a double bond (C=C) between the α-carbon and the oxygen. 
I and II are both enols of compound X because they both have a double bond between the α-carbon and the oxygen, which is the defining feature of an enol. 
III does not have a double bond between the α-carbon and the oxygen, so it is not an enol.

Which of the Following Compounds Is an Enol of Compound