Identify the correct decreasing order of the number of enolizable protons for the following compounds: (I) (II) (III)

Step-by-step solution

The number of enolizable protons in a compound is equal to the number of hydrogen atoms attached to the -carbon(s) adjacent to the carbonyl group. 1. Compound (I) is acetaldehyde ( CH ₃ CHO ). It has one -carbon (the methyl group) which is attached to 3 hydrogen atoms. Thus, it has 3 enolizable protons. 2. Compound (II) is -valerolactone (a cyclic ester). The carbonyl group is adjacent to an oxygen atom on one side and a CH ₂ group on the other side. The -carbon has 2 hydrogen atoms. Thus, it has 2 enolizable proto