Q.Write the IUPAC name of benzylamine.
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Amines are named under two systems. Common names: 'alkyl amine' (alkyl-group name plus suffix -amine), with mixed-amine substituents listed alphabetically and di-/tri- prefixed for identical groups; C6H5-NH2 is aniline, the parent name for other arylamines (e.g. p-toluidine, p-bromoaniline). IUPAC names: a primary amine's name replaces the parent alkane's final -e with -amine (family name alkanamine) plus a locant (e.g. propan-1-amine); with two or more amino groups the alkane's -e is retained and di-/tri- prefixes with locants are used (e.g. hexane-1,6-diamine). Secondary/tertiary amines are named as N-substitu …
Table 13.2 itself lists benzylamine's IUPAC name directly. …
Step 1. Recall benzylamine's structure. Benzylamine is C6H5-CH2-NH2 -- a benzene ring attached, via a -CH2- carbon, to the amino group (the amino group is on the SIDE CHAIN, not directly on the ring).
Step 2. Apply IUPAC naming (section 13.2.2). Since the amino group sits on a chain carbon (the benzylic CH2), not directly on the aromatic ring itself, this is named as a substituted METHANAMINE (the one-carbon parent chain bearing -NH2), with the ring cited as a phenyl substituent on that carbon. …
Recognising benzylamine's -NH2 sits on a side-chain methanamine carbon (not directly on the ring) and confirming the …
- Naming it as a substituted 'benzenamine' (as if -NH2 were directly on the ring, giving something like 'phenylamine'), confusing benzylamine (amino group on a side-chain CH2) with aniline (amino group directly on the ring). …
- CBSE 2026Set ANNUAL1 markMCQQ.The IUPAC name of (CH3)3C-NH2 is:(a) Trimethyl amine(b) 2-Methylpropan-2-amine(c) 2-Methylpropan-1-amine(d) 2-Methylpropan amine
›Reveal solutionSolution
(CH3)3C−NH2 (tert-butylamine) is named 2-methylpropan-2-amine by IUPAC rules.
To name an amine by IUPAC substitutive nomenclature, the longest carbon chain containing the carbon bearing the −NH2 group is selected as the parent, and the suffix '-amine' is added with a locant, while other substituents are cited as prefixes with their own locants.
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- CBSE 2026Set ANNUAL1 markMCQQ.The correct IUPAC name for CH2=CHCH2NHCH3 is :(a) Allylemethylamine(b) 2-amino-4-pentene(c) 4-aminopent-1-ene(d) N-methylprop-2-en-1-amine
›Reveal solutionSolution
CH₂=CH–CH₂–NH–CH₃ is named as a propene chain bearing an amine at C1 and an N-methyl substituent, giving N-methylprop-2-en-1-amine.
Structure: CH₂=CH–CH₂–NH–CH₃
- Identify the parent chain: the longest carbon chain containing the –NH– nitrogen's point of attachment is the 3-carbon allyl chain, CH₂=CH–CH₂–, which as a substituted amine is named as prop-2-en-1-amine (double bond between C2–C3, amine at C1).
- The nitrogen carries an extra methyl substituent (–CH₃) instead of a second hydrogen, so this substituent is cited with the italic locant N- to show it is on nitrogen, not on the carbon chain: N-methyl.
- Combine: N-methylprop-2-en-1-amine. …
- CBSE 2025Set ANNUAL1 markQ.Write the structural formula of N, N-dimethylethanamine.
›Reveal solutionSolution
N,N-dimethylethanamine: CH3CH2−N(CH3)2 (both N-H's of ethanamine replaced by methyl groups).
'Ethanamine' is the IUPAC name for ethylamine, CH3CH2−NH2. The prefix 'N,N-dimethyl' means two methyl groups replace the two hydrogens on the nitrogen atom itself:
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- CBSE 2024Set ANNUAL1 markMCQQ.The IUPAC name of CH3-CH(CH3)-NH-CH3 is -(a) N-methyl propan-2-amine(b) N-methyl propanamine(c) N,N-dimethylbutanamine(d) 2-methyl-N-methylbutanamine
›Reveal solutionSolution
Name the longest carbon chain bearing the -NH- group as the parent "...amine", and cite the second alkyl group on nitrogen with an italic N- locant.
Structure: CH3–CH(CH3)–NH–CH3, i.e. (CH3)2CH–NH–CH3 — this is a secondary amine: an isopropyl group and a methyl group both attached to the same nitrogen.
IUPAC naming for secondary/tertiary amines:
- Identify the parent chain carrying the nitrogen with the longest carbon skeleton directly bonded to N: here that's the 3-carbon isopropyl fragment, CH3–CH(NH...)–CH3, named as propan-2-amine (amine group on C-2 of propane). …
- CBSE 2023Set F1 markMCQQ.The IUPAC name of CH3-CH(NH2)-CH3 is(a) Propyl amine(b) Isopropyl amine(c) Propan-2-amine(d) Propan-1-amine
›Reveal solutionSolution
CH3-CH(NH2)-CH3 is a 3-carbon chain with -NH2 on C2 → propan-2-amine.
The compound CH3-CH(NH2)-CH3 has a parent chain of three carbons (propane) with an amino group -NH2 on the central carbon (position 2). The IUPAC name is formed as propan-2-amine (the -e of propane is dropped before …
- CBSE 2023Set ANNUAL1 markQ.Write the IUPAC name of C2H5-N(CH3)-CH3 (N-ethyl-N-methylmethanamine skeleton: C2H5 and two CH3 groups on N). OR Draw the structural formula of Butan-2-amine.
›Reveal solutionSolution
The longest carbon chain attached to N (ethyl, 2 carbons) is chosen as the parent 'ethanamine'; the two remaining methyl groups on N are cited as N,N-dimethyl substituents.
C₂H₅–N(CH₃)–CH₃ is a tertiary amine with three groups on nitrogen: one ethyl and two methyl groups. IUPAC naming of amines picks the longest carbon chain bonded to the nitrogen as the parent chain (here, the 2-carbon ethyl group, giving the parent 'ethanamine'), and cites every other group atta …
- CBSE 2023Set ANNUAL1 markMCQQ.The IUPAC name of the compound
CH₃ - N - C - CH₂ - CH₃ | | CH₃ C₂H₅ (N bonded to a CH₃ on the left and a CH₃ below it; the adjacent carbon bonded to a CH₃ above, a C₂H₅ below, and continuing to -CH₂-CH₃) is -CH₃ |(i) 2-Methyl-N-methyl-N-ethylpentanamine(ii) 2-Methyl-N,N-dimethylbutanamine(iii) 3-Methyl-N,N-dimethylpentan-3-amine(iv) 3-Methyl-N,N-dimethylpentan-2-amine›Reveal solutionSolution
Pick the longest carbon chain running through the carbon attached to nitrogen, number to give the amine (and thus the N-substituent carbon) the lowest locant, and cite the branch and the two N-methyls as substituents.
The amine nitrogen is bonded to two methyl groups and to a carbon (call it C*) that itself carries: a methyl group, an ethyl group, and continues into a -CH₂-CH₃ chain.
To find the parent chain, take the longest carbon chain running through C* (the carbon bearing the amino group): combining the ethyl branch on one side with the -CH₂-CH₃ continuation on the other side through C* gives a 5-carbon chain (pentane): CH3−CH2−C∗(CH3)(NMe2)−CH2−CH3, with C* as carbon 3 of that chain (the methyl group on C* becomes a 3-methyl substituent, and the shorter methyl-only branch is …
- CBSE 2022Set ANNUAL1 markMCQQ.The IUPAC name of CH3–CH(NH2)–CH2–CHO is –(a) 3-Aminobutanal(b) 4-Oxobut-2-amine(c) 2-Amino propanal(d) 4-Oxo but-3-amine
›Reveal solutionSolution
CH3–CH(NH2)–CH2–CHO is a 4-carbon chain named as a butanal with an amino substituent, giving 3-aminobutanal.
Since the aldehyde group (–CHO) is the senior (principal) characteristic group, the chain is numbered from the CHO carbon as C1: C1(CHO)–C2(CH2)–C3(CH–NH2)–C4(CH3). The parent chain is b …
- CBSE 2022Set ANNUAL1 markMCQQ.The IUPAC name of C2H5–N(C2H5)–CH2CH2CH3 is –(a) N,N-Diethylpropanamine(b) N,N-Diethylheptan-1-amine(c) N,N-Diethylpropan-2-amine(d) N,N-Diethylpropan-3-amine
›Reveal solutionSolution
The nitrogen carries two ethyl groups and one propyl group attached through its terminal (C1) carbon, giving N,N-diethylpropan-1-amine (written N,N-diethylpropanamine).
C2H5–N(C2H5)–CH2CH2CH3 is a tertiary amine. The longest chain attached to N through a single bond at its end carbon is propyl (3 carbons), so the parent name is propanamine (locant 1 is the default/implied positi …
- CBSE 2021Set ANNUAL1 markMCQQ.The IUPAC name for CH2=CHCH2NHCH3 is –(a) N-methylprop-1-en-3-amine(b) N-methylprop-2-en-1-amine(c) 4-aminebut-1-ene(d) 4-aminepent-1-ene
›Reveal solutionSolution
Number the 3-carbon allyl chain from the end bearing the −NH− group; the double bond is at C2–C3.
The compound is CH2=CH−CH2−NH−CH3. The parent chain is the 3-carbon chain carrying the principal characteristic group (−NH−), i.e. propene: C1(H2N-attached)−C2=C3. Numbering to give the amine-bearing carbon the lowest locant: C1 bears the NHCH3 group, and the double bond runs between C2 and C3, so the parent is prop-2-en-1-amine. The extra methyl group on nitrogen is indicated by the italic locant N: N-methyl. …
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