Which one of the following classes of organic compound does not contain the carbonyl (C=O) group? A) aldehydesB) carboxylic acidsC) ketonesD) alcoholsE) esters

Answer: alcohols

Explanation:

The carbonyl group refers to C=O. It is contained in aldehyde, Ketones, carboxylic acids, esters, amides and acyl chlorides. They are not found in alcohols. The alchols are generally ROH. They do not contain any carbon-oxygen unsaturated bond in their structure hence the answer.