What class of compound is C2H5COOH?

What class of compound is C2H5COOH?

• A. Carboxylic acid
• B. Alcohol
• C. Aldehyde
• D. Alkane

Answer: (A)

Recognizing the carboxyl group was the key idea. The molecule C2H5COOH contains a -COOH group, a carbonyl carbon double-bonded to an oxygen and also bonded to a hydroxyl group on the same carbon. That specific arrangement defines a carboxylic acid. The -COOH group also explains the acidic behavior of these compounds, since the hydrogen on the -OH can be lost to form a stable carboxylate ion by resonance. If you compare with the other classes: an alcohol has a separate -OH group attached to a carbon, not as part of -COOH; an aldehyde has a -CHO group at the end of the carbon chain; an alkane is just carbon-hydrogen chains with no carbonyl or -OH groups. So the presence of the -COOH group makes it a carboxylic acid.

Recognizing the carboxyl group was the key idea. The molecule C2H5COOH contains a -COOH group, a carbonyl carbon double-bonded to an oxygen and also bonded to a hydroxyl group on the same carbon. That specific arrangement defines a carboxylic acid. The -COOH group also explains the acidic behavior of these compounds, since the hydrogen on the -OH can be lost to form a stable carboxylate ion by resonance.

If you compare with the other classes: an alcohol has a separate -OH group attached to a carbon, not as part of -COOH; an aldehyde has a -CHO group at the end of the carbon chain; an alkane is just carbon-hydrogen chains with no carbonyl or -OH groups. So the presence of the -COOH group makes it a carboxylic acid.