Which of the following compounds contains an aldehyde functional group?

• A. ${\mathrm{CH}}_3\mathrm{CH}{2}_{}\mathrm{OH}$
• B. ${\mathrm{CH}}_3\mathrm{COOH}$
• C. ${\mathrm{CH}}_3\mathrm{COCH}{3}_{}$
• D. ${\mathrm{CH}}_3\mathrm{CHO}$

Answer: (D)

Verified step by step guidance

1. Identify the functional groups present in each compound by analyzing their molecular formulas and structures.
2. Recall that an aldehyde functional group is characterized by the presence of a carbonyl group (C=O) bonded to at least one hydrogen atom, typically represented as -CHO.
3. Examine the first compound, \(CH_3CH_2OH\), which contains an -OH group attached to an alkyl chain, indicating it is an alcohol, not an aldehyde.
4. Look at the second compound, \(CH_3COOH\), which has a carboxyl group (-COOH), characteristic of carboxylic acids, not aldehydes.
5. Analyze the third compound, \(CH_3COCH_3\), which contains a carbonyl group bonded to two carbon atoms, identifying it as a ketone, not an aldehyde. The aldehyde group is represented by \(CH_3CHO\), where the carbonyl carbon is bonded to a hydrogen atom.