Advertisements
Advertisements
Question
Give a plausible explanation for the following:
Why are aliphatic amines stronger bases than aromatic amines?
Advertisements
Solution 1
Due to the −R effect of the benzene ring, the electrons on the N- atom are less available in the case of aromatic amines. Therefore, the electrons on the N-atom in aromatic amines cannot be donated easily. This explains why aliphatic amines are stronger bases than aromatic amines.
Solution 2
Aromatic amines are far less basic than ammonia and aliphatic amines because of the following reasons:
- Due to resonance in aniline and other aromatic amines, the lone pair of electrons on the nitrogen atom gets delocalised over the benzene ring and thus it is less easily available for protonation. Therefore, aromatic amines are weaker bases than ammonia and aliphatic amines.
- Aromatic amines are more stable than corresponding protonated ions; Hence, they have very little tendency to combine with a proton to form a corresponding protonated ion, and thus they are less basic.
APPEARS IN
RELATED QUESTIONS
Identify the weakest base amongst the following :
(a) p- methoxyaniline
(b) o-toluidine
(c) benzene - 1, 4 - diamine
(d) 4 - aminobenzoic acid
Give reasons for the following: (CH3)2NH is more basic than (CH3)3N in an aqueous solution.
Arrange the following in increasing order of their basic strength :
C6H5 – NH2, C6H5 – CH2 – NH2, C6H5 – NH – CH3
How will you convert Cl−(CH2)4−Cl into hexan-1, 6-diamine?
Arrange the following in increasing order of their basic strength:
C2H5NH2, (C2H5)2NH, (C2H5)3N, C6H5NH2
Complete the following acid-base reaction and name the product:
\[\ce{CH3CH2CH2NH2 + HCl ->}\]
Complete the following acid-base reaction and name the product:
\[\ce{(C2H5)3N + HCl ->}\]
Arrange the following:
In increasing order of boiling point:
C2H5OH, (CH3)2NH, C2H5NH2
Accomplish the following conversion:
Benzene to m-bromophenol
Choose the most correct option.
Which one of the following compounds has the highest boiling point?
Answer in one sentence.
Arrange the following amines in increasing order of boiling points.
n-propylamine, ethylmethyl amine, trimethylamine.
The CORRECT decreasing order of boiling points is:
Among the following isomeric amines, an amine having highest boiling point is:
Assertion: N-Ethylbenzene sulphonamide is soluble in alkali.
Reason: Hydrogen attached to nitrogen in sulphonamide is strongly acidic.
Account for the following:
N-ethylethanamine boils at 329.3 K and butanamine boils at 350.8 K, although both are isomeric in nature.
Which of the following have less melting point than amine?
Which of the following amines form maximum hydrogen bonds within themselves?
Arrange the following in increasing order of their boiling point:
C2H5OH, C2H5NH2, (C2H5)3N
