Consider the following compounds: I. Cyclohexa-2,4-dien-1-one II. Pentane-2,4-dione III. Ethyl 3-oxobutanoate IV. Propan-2-one The correct decreasing order of their enol content is:

Step-by-step solution

The enol content of a compound depends on the thermodynamic stability of its enol form relative to its keto form. Compound I (Cyclohexa-2,4-dien-1-one) tautomerizes to phenol. The resulting enol form is aromatic, which provides exceptional thermodynamic stability. Its enol content is nearly 100 % . Compound II (Pentane-2,4-dione) is a -diketone. Its enol form is stabilized by extended conjugation and strong intramolecular hydrogen bonding, forming a stable six-membered chelate ring. Its enol content is significant