Q.1. The correct order of the basic strength of methyl substituted amines in aqueous solution is: (2019)
A: (CH3)2NH > CH3NH2 > (CH3)3N
B: (CH3)3N > CH3NH2 > (CH3)2NH
C: (CH3)3N > (CH3)2NH > CH3NH2
D: CH3NH2 > (CH3)2NH > (CH3)3N
In aqueous solution, electron donating inductive effect, solvation effect (H-bonding) and steric hindrance all together affect basic strength of substituted amines
Q.2. Nitration of aniline in strong acidic medium also gives m-nitroaniline because (2018)
A: In spite of substituents nitro group always goes to only m-position.
B: In electrophilic substitution reactions amino group is meta directive.
C: In absence of substituents nitro group always goes to m-position
D: In acidic (strong) medium aniline is present as anilinium ion.
In acidic medium aniline is protonated to form anilinium ion which is metadirecting.
Q.3. Which of the following reactions is appropriate forconverting acetamide to methanamine ? (2017)
A: Hoffmann hypobromamide reaction
B: Stephens reaction
C: Gabriels phthalimide synthesis
D: Carbylamine reaction
This reaction is known as hoffmann hypobromamide reaction.
Q.4. The correct statement regarding the basicity of arylamines is : (2016)
A: Arylamines are generally more basic than alkylamines, because the nitrogen atom in arylamines is sp-hybridized.
B: Arylamines are generally less basic than alkylamines because the nitrogen lone pair electrons are delocalized by interaction with the aromatic ring π electrons system.
C: Arylamines are generally more basic than alkylamines because the nitrogen lone pair electrons are not delocalized by interaction with the aromatic ring π electron system.
D: Arylamines are generally more basic than alkylamines because of aryl group
In arylamines, lone pair of electrons on nitrogen atom is delocalised over the benzene ring, thus, not available for donation. So, arylamines are less basic than alkylamines.
Q.5. The electrolytic reduction of nitrobenzene in strongly acidic medium produces: (2015)
Electrolytic reduction of nitrobenzene in weakly acidic medium gives aniline but in strongly acidic medium, it gives para-amino phenol obviously through the acid catalysed rearrangement of initially formed phenyl hydroxyl amine.
Q.6. In the following reaction, the product (A) (2014)
The above reaction is a coupling reaction of aniline with diazonium salt to give azo benzene compound. This coupling reaction takes place at the para-position to - NH2 group of benzene. This reaction act as electrophilic substitution reaction of aniline.
Q.7. Which of the following will be most stable diazonium salt? (2014)
Diazonium salt containing aryl group directly linked to the nitrogen atom is most stable due to resonance stabilization between the benzene nucleus and N-atom.
[Resonance structure of benzene diazonium ion]