Consider the following statements about the naming of amines.
(A) In the common system, an aliphatic amine is named by prefixing the alkyl group to amine, written as one word, for example methylamine.
(B) While naming arylamines in the IUPAC system, the suffix ‘e’ of arene is replaced by ‘amine’, so C6H5NH2 is named benzenamine.
(C) Aniline, the common name of C6H5NH2, is not an accepted IUPAC name.
(D) In the common names of secondary and tertiary amines, the prefix di or tri is appended before the name of the alkyl group when two or more groups are the same.
(E) In the IUPAC system, o-toluidine is named 3-methylaniline.
Which of the statements given above are correct? Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A), (B) and (D) only
Amines have common names (alkylamine, aniline) and IUPAC names (alkanamine, benzenamine). Both systems are in use, and for some amines the common name is also accepted by IUPAC.
(A) In the common system, an aliphatic amine is named by prefixing the alkyl group to amine, written as one word, for example methylamine. — True. The alkyl group and “amine” are joined into one word: methylamine, ethylamine.
(B) While naming arylamines in the IUPAC system, the suffix ‘e’ of arene is replaced by ‘amine’, so C6H5NH2 is named benzenamine. — True. Benzene loses its final ‘e’ and takes ‘amine’: benzen + amine = benzenamine.
(C) Aniline, the common name of C6H5NH2, is not an accepted IUPAC name. — False. Aniline is also an accepted IUPAC name; so C6H5NH2 may be called aniline or benzenamine.
(D) In the common names of secondary and tertiary amines, the prefix di or tri is appended before the name of the alkyl group when two or more groups are the same. — True. For example, (C2H5)2NH is diethylamine and (CH3)3N is trimethylamine.
(E) In the IUPAC system, o-toluidine is named 3-methylaniline. — False. In o-toluidine the methyl group is on the carbon next to the carbon carrying –NH2 (the ortho position).
That carbon gets the number 2, so the name is 2-methylaniline.
NCERT (2026-27 edition):
9.3 Nomenclature – “In common system, an aliphatic amine is named by prefixing alkyl group to amine, i.e., alkylamine as one word (e.g., methylamine). In secondary and tertiary amines, when two or more groups are the same, the prefix di or tri is appended before the name of alkyl group.”
“…C6H5NH2 is the simplest example of arylamine. In common system, it is known as aniline. It is also an accepted IUPAC name. While naming arylamines according to IUPAC system, suffix ‘e’ of arene is replaced by ‘amine’. Thus in IUPAC system, C6H5–NH2 is named as benzenamine.”
Table 9.1: Nomenclature of Some Alkylamines and Arylamines (one row) – Common name: o-Toluidine; IUPAC name: 2-Methylaniline