Chemistry Multiple Choice Questions on “Amines Nomenclature – 2”.
1. What is the common name of the simplest aromatic amine?
a) Aniline
b) Benzylamine
c) Benzenamine
d) Aminobenzene
Answer: a
Clarification: The simplest amine is C6H5NH2 and is known as aniline. This name is also accepted as the IUPAC name. Its actual IUPAC name is benzenamine, or it may also be written as aminobenzene.
2. What is the substituent group in 2-methylbezebamine?
a) Methyl group
b) Amino group
c) Benzene ring
d) Methyl and amino groups
Answer: a
Clarification: 2-Methylbenzenamine is an aromatic amine which is a derivative of benzenamine with the presence of a methyl group as substituent at the ortho position.
3. Identify the substituent in p-anisidine?
a) CH3
b) OCH3
c) NH2
d) COCH3
Answer: b
Clarification: p-Anisidine is better known as 4-methoxybenzenamine, which has a methoxy group at para position to the amino group. The common name anisidine is derived from the common names anisole and aniline.
4. What is the correct IUPAC name of the compound which has a benzene ring substituted with amino group at one position and a bromine atom at a position para to it?
a) 4-Aminobromobenzene
b) 4-Bromobenylamine
c) 4-Bromoaniline
d) p-Bromoaniline
Answer: c
Clarification: This compound is an aromatic compound which is a bromo derivative of aniline and is named such that aniline is principle group. The position of bromine is indicated by number 4 which corresponds to the para position.
5. What is the IUPAC name of the shown compound?
a) N-Methyl-N-ethylbenzenamine
b) N-Methyl-N-phenylethanamine
c) N-Ethyl-N-methylbezenamine
d) N-Ethyl-N-phenylmethanamine
Answer: c
Clarification: There are three substituents viz., methyl group, ethyl group and phenyl group. Since the phenyl group is the largest, it is considered as the main group with CH3 and C2H5 acting as substituents. Also, ethyl is named before methyl due to alphabetical reasons.
6. What is the correct name of the compound with two amino groups around a benzene ring at opposite (para) positions?
a) Benzenediamine
b) 4-Aminobenzenamine
c) p-Aminoaniline
d) Benzene-1,4-diamine
Answer: d
Clarification: Both the amino groups (at para position to each other) are given equal importance and is named by giving the prefix di to the main compound. The prefix is also numbered 1 and 4, representing the positions at which amino groups are present in the benzene ring.
7. Identify the correct name of the shown compound.
a) 4-Amino-1,1-Dimethylcyclohexane
b) 4,4-Dimethylcyclohexan-1-amine
c) 4,4-Dimethylaniline
d) N-(4,4-Dimethylcyclohexyl)amine
Answer: b
Clarification: This is an aliphatic primary amine which is cyclic in structure. The two methyl groups at C-4 position act as substituents of the cyclohexyl ring with the amino group at C-1 position.
8. p-tert-Butyl aniline is a tertiary amine.
a) True
b) False
Answer: b
Clarification: p-tert-Butyl aniline is a derivative of aniline (which is a primary amine) with a tert-Butyl substituent ((CH3)3C) at para position. Hence, it is a primary amine.
9. Identify the incorrect name of the compound formed when two hydrogen atoms of ammonia are replaced by phenyl groups.
a) Diphenylamine
b) N-Phenylaniline
c) N-Phenylbenzenamine
d) N,N-Diphenylaniline
Answer: d
Clarification: It is a secondary aromatic amine that will be formed. One of the phenyl groups will be considered as a substituent on nitrogen atom (N-phenyl) and the other will act as aniline with the N atom.
10. How many isomeric amines are possible of the formula C4H11N.
a) 5
b) 8
c) 10
d) 11
Answer: b
Clarification: Eight isomeric amines with the formula C4H11N are possible. Four of them are primary amines, three are secondary and one of them is a tertiary amine.
11. What is the IUPAC name of CH3-NH-CH2-CH(NO2)-CH3 ?
a) N-Methyl-2-nitropropanamine
b) 1-Aminomethyl-2-nitropropane
c) N-(2-Nitropropyl)methanamine
d) N-Methyl-2-methylnitropropanamine
Answer: a
Clarification: This compound contains all substituent functional groups, and is named as a derivative of the compound containing the functional group which occurs first in alphabetical order, i.e., amino group.
12. Identify the correct naming of H2NCH2CH2OH.
a) 2-Hydroxyethanamine
b) 2-Aminoethanol
c) Ethane-2-hydroxy-1-amine
d) 1-Aminoethan-2-ol
Answer: b
Clarification: In case of multiple functional groups, the amino group is considered as substituent and the other is regarded as the principle functional group and is given the lower carbon position. In this case, the compound is named as a derivative of ethanol.
13. Which of the following names are incorrect according to IUPAC?
a) 1-Phenylethanamine
b) N-Methylaniline
c) N-Butylaminoethane
d) Propane-1,2-diamine
Answer: c
Clarification: The larger alkyl group should be considered as parent chain, which in this case is butyl group. Thus, the correct name will be N-ethylbutanamine.
14. If NH2 and NO2 exist in the same compound, it will be named as a derivative of the amino compound.
a) True
b) False
Answer: a
Clarification: Since amino group (NH2) comes alphabetically ahead of nitro group (NO2), the compound is named as a derivative of amine with nitro as a substituent.