Which Action Could Produce a Carbonyl Group

Question

Which action could produce a carbonyl group?
A) the replacement of the -OH of a carboxyl group with hydrogen
B) the addition of a thiol to a hydroxyl
C) the addition of a hydroxyl to a phosphate
D) the replacement of the nitrogen of an amine with oxygen
E) the addition of a sulfhydryl to a carboxyl

Accepted Answer

A carbonyl group consists of a carbon atom double-bonded to an oxygen atom (C=O). The replacement of the -OH of a carboxyl group (COOH) with hydrogen would produce a carbonyl group, as it removes the hydroxyl group and leaves the double-bonded oxygen atom attached to the carbon atom. The other options do not involve the formation of a carbonyl group.