Question

Which of the following is a primary amine?

• A. 1-Butylamine
• B. Isobutylamine
• C. N-Butylamine
• D. All of these

Hint:

To identify primary amines, look for the nitrogen atom bonded to one carbon chain and two hydrogen atoms.

Answer 1

The Correct Option is D

An amine is classified as primary, secondary, or tertiary based on the number of carbon atoms attached to the nitrogen atom in the amine group (-NH₂). The classification is as follows:

• Primary amine: The nitrogen atom is bonded to one carbon atom and two hydrogen atoms. A primary amine has the structure R-NH₂, where R represents an alkyl or aryl group.
• Secondary amine: The nitrogen atom is bonded to two carbon atoms and one hydrogen atom.
• Tertiary amine: The nitrogen atom is bonded to three carbon atoms and no hydrogen atoms.

Analysis of each option:

• 1-Butylamine: This is a primary amine. In this compound, the amine group (-NH₂) is attached to a primary carbon atom, meaning the nitrogen is connected to one carbon (the -CH₂- group of butyl) and two hydrogen atoms. Therefore, 1-butylamine is a primary amine.
• Isobutylamine: This is also a primary amine. Despite being a branched-chain alkyl group, the nitrogen in isobutylamine is attached to a primary carbon atom (the -CH₂ group of the isobutyl chain). Thus, isobutylamine is classified as a primary amine.
• N-Butylamine: N-butylamine is another primary amine. The nitrogen atom in this molecule is connected to a butyl group (C₄H₉), and the amine group is attached to a primary carbon atom, making this compound a primary amine as well.

Conclusion: All three compounds, 1-butylamine, isobutylamine, and N-butylamine, are primary amines because in all of them, the nitrogen is attached to a primary carbon. Therefore, the correct answer is Option 4: All of these.