Which of the following compounds is classified as an amine?

• A. ${\mathrm{CH}}_3\mathrm{COOH}$ (acetic acid)
• B. ${\mathrm{CH}}_3\mathrm{OCH}{3}_{}$ (dimethyl ether)
• C. ${\mathrm{CH}}_3\mathrm{OH}$ (methanol)
• D. ${\mathrm{CH}}_3\mathrm{NH}{2}_{}$ (methylamine)

Answer: (D)

Verified step by step guidance

1. Identify the functional group characteristic of an amine, which is a nitrogen atom bonded to one or more alkyl or aryl groups, typically represented as \(\mathrm{R-NH_2}\), \(\mathrm{R_2NH}\), or \(\mathrm{R_3N}\).
2. Examine each compound's structure to determine its functional group: acetic acid (\(\mathrm{CH_3COOH}\)) contains a carboxylic acid group (\(\mathrm{-COOH}\)), dimethyl ether (\(\mathrm{CH_3OCH_3}\)) contains an ether group (\(\mathrm{-O-}\)), methanol (\(\mathrm{CH_3OH}\)) contains an alcohol group (\(\mathrm{-OH}\)), and methylamine (\(\mathrm{CH_3NH_2}\)) contains an amine group (\(\mathrm{-NH_2}\)).
3. Recall that amines are derivatives of ammonia (\(\mathrm{NH_3}\)) where one or more hydrogen atoms are replaced by alkyl or aryl groups, which is the case for methylamine where one hydrogen is replaced by a methyl group.
4. Compare the functional groups of all given compounds and identify which one contains the nitrogen atom bonded to carbon and hydrogen atoms, characteristic of an amine.
5. Conclude that the compound with the \(\mathrm{-NH_2}\) group attached to a methyl group, methylamine (\(\mathrm{CH_3NH_2}\)), is classified as an amine.