Which of the following compounds contains a $\mathrm{carbonyl}$ functional group?

• A. ${\mathrm{CH}}_3\mathrm{OH}$ (methanol)
• B. ${\mathrm{CH}}_3\mathrm{NH}{2}_{}$ (methylamine)
• C. ${\mathrm{CH}}_3\mathrm{COOH}$ (acetic acid)
• D. ${\mathrm{CH}}_4$ (methane)

Answer: (C)

Verified step by step guidance

1. Understand that a carbonyl functional group consists of a carbon atom double-bonded to an oxygen atom, represented as \(\mathrm{C=O}\).
2. Examine each compound's structure to identify the presence or absence of the carbonyl group:
3. 1. Methanol (\(\mathrm{CH_3OH}\)) contains a hydroxyl group (\(\mathrm{-OH}\)) but no carbonyl group.
4. 2. Methylamine (\(\mathrm{CH_3NH_2}\)) contains an amino group (\(\mathrm{-NH_2}\)) but no carbonyl group.
5. 3. Acetic acid (\(\mathrm{CH_3COOH}\)) contains a carboxyl group, which includes a carbonyl (\(\mathrm{C=O}\)) bonded to a hydroxyl group, so it has a carbonyl functional group.
6. 4. Methane (\(\mathrm{CH_4}\)) is a simple alkane with only single bonds and no carbonyl group.