Chemistry · Amines · NEET
Take ammonia, NH3. It has one nitrogen atom joined to three hydrogen atoms. An amine is what you get when you remove one or more of those hydrogen atoms and put a carbon group (alkyl like CH3, or aryl like C6H5) in its place. The nitrogen and its lone pair stay. Because the whole family is built by editing NH3, we call amines 'derivatives of ammonia'. This is the exact wording NCERT uses, so learn it for NEET.
Ammonia is NH3: nitrogen with three hydrogens and one lone pair. An amine has at least one of those hydrogens replaced by a carbon group. Example: replace one H in NH3 with CH3 and you get CH3-NH2 (methylamine), which is an amine. Both have a nitrogen with a lone pair, so both are basic, but the amine carries a carbon chain that ammonia does not.
R is a short symbol for any alkyl or aryl group - a carbon-containing group. For example, R can be CH3 (methyl), C2H5 (ethyl), or C6H5 (phenyl). So R-NH2 is a general way to write any primary amine without naming a specific one. When you see R2-NH it means two carbon groups on the nitrogen, and R3-N means three.
Yes, aniline (C6H5-NH2) is an amine. Here one hydrogen of NH3 is replaced by a phenyl group (the benzene ring, C6H5). Because the carbon group attached is a benzene ring (aryl), aniline is called an aromatic amine or aryl amine. It is still a derivative of ammonia - the -NH2 group is the giveaway.
The functional group is the amino group, which is the nitrogen with its lone pair (written -NH2, >NH, or >N- depending on how many H atoms are left). This nitrogen and its lone pair are what make all amines behave alike: they act as weak bases and as nucleophiles. Spotting the nitrogen-with-lone-pair is how you recognise an amine in any NEET structure.
Amines are one of the highest-scoring chapters in NEET organic chemistry - almost every year there are 1 to 2 questions, and the whole chapter (basicity order, tests, diazonium salts, preparations) is built on this one idea that amines are edited ammonia. If you understand that the nitrogen and lone pair come straight from NH3, the basicity, the carbylamine test, and the reactions all make sense.
Which of the following amines will give the carbylamine test?
The product formed by the reaction of an aldehyde with a primary amine is:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Amines are organic compounds because they always contain at least one carbon group attached to the nitrogen. Ammonia itself (NH3) is inorganic, but the moment you attach a carbon group you get an organic amine.
You can replace one, two, or all three hydrogens of NH3. Replacing one gives a primary amine (R-NH2), two gives a secondary amine (R2-NH), and all three gives a tertiary amine (R3-N). This count is the basis of amine classification.
Yes. No matter how many H atoms you replace, the nitrogen keeps its one lone pair of electrons. This lone pair is why amines, like ammonia, act as weak bases and as nucleophiles in reactions.
Yes. CH3-NH2 (methylamine) is NH3 with one hydrogen swapped for a methyl group (CH3). It is the simplest example of a derivative of ammonia and a primary amine.
A primary amine is written R-NH2, a secondary amine as R2-NH, and a tertiary amine as R3-N, where R is any alkyl or aryl group. The saturated aliphatic amine general molecular formula is CnH2n+3N.
