NEET

Which one of the following is the strongest base in aqueous solution ?

Methylamine
Trimethylamine
Aniline
Dimethylamine

Solution

Aromatic amines are less basic than aliphatic amines.Among aliphatic amines the order of basicity is 2°> 1° >3°. The electron density is decreased in 3°amine due to crowding of alkyl group over N atom which makes the approach and bonding by a proton relatively difficult. Therefore the basicity decreases. Further Phenyl group show – I effect, thus decreases the electron density on nitrogen atom and hence the basicity.
∴ dimethylamine (2° aliphatic amine) is strongest base among given choices.
∴ The correct order of basic strength is Dimethylamine > Methyl amine > Trimethyl amine > Aniline.

a
b
c
d

Solution

Which of the following statements about primary amines is‘False’ ?

Alkylamines are stronger bases than aryl amines
Alkyl amines react with nitrous acid to produce alcohols
Aryl amines react with nitrous acid to produce phenols
Alkyl amines are stronger bases than ammonia

Solution

Aryl amines do not produce phenol on treatment with nitrous acid.

Acetamide is treated with the following reagents separately.Which one of these would yield methylamine?

NaOH –Br₂
Sodalime
Hot conc. H₂SO₄
PCl₅

Solution

Nitrobenzene can be prepared from benzene by using a mixture of conc. HNO₃ and conc. H₂SO₄ in the mixture, nitric acid acts as a/an :

acid
base
catalyst
reducing agent

Solution

\(HONO_{2} + H_{2}SO_{4} \rightarrow NO_{2}^{+} + H_{2}O + HSO_{4}^{-}\)
Nitric acid acts as a base by accepting a proton.

a
b
c
d

Solution

a
b
c
d

Solution

Which one of the following on reduction with lithium aluminium hydride yields as econdary amine?

Methyl isocyanide
Acetamide
Methyl cyanide
Nitroethane

Solution

Anilinium hydrogen sulphate on heating with sulphuric acid at 453-473 K produces

benzene sulphonic acid
anthranilic acid
aniline
sulphanilic acid

Solution

a
b
c
d

Solution

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