Given the structure ${\mathrm{CH}}_3-\mathrm{NH}-{\mathrm{CH}}_3$, how would you classify this amine?

• A. Quaternary ammonium compound
• B. Tertiary amine
• C. Secondary amine
• D. Primary amine

Answer: (C)

Verified step by step guidance

1. Identify the number of alkyl or aryl groups attached directly to the nitrogen atom in the amine structure. The given structure is CH\_3-NH-CH\_3, where the nitrogen is bonded to two carbon-containing groups (two methyl groups).
2. Recall the classification of amines based on the number of carbon groups attached to the nitrogen: Primary amine has one alkyl/aryl group, secondary amine has two, tertiary amine has three, and quaternary ammonium compounds have four substituents and carry a positive charge.
3. Count the substituents on the nitrogen: here, the nitrogen is bonded to two methyl groups (CH\_3) and one hydrogen atom (H). This means there are two alkyl groups attached to the nitrogen.
4. Since the nitrogen has two alkyl groups attached, classify the amine as a secondary amine.
5. Confirm that the structure does not have a positive charge or four substituents, so it is not a quaternary ammonium compound, and it is not primary or tertiary based on the number of alkyl groups.