✓ Board-verified
Chemistry · 2025 · 4 marks
CBSE 2025 · Region 7 · Set 1 · Q30
Amines are usually formed from amides, imides, halides, nitro compounds, etc. They exhibit hydrogen bonding which influences their physical…
Amines are usually formed from amides, imides, halides, nitro compounds, etc. They exhibit hydrogen bonding which influences their physical properties. In alkyl amines, a combination of electron releasing, steric and H-bonding factors influence the stability of the substituted ammonium cations in protic polar solvents and thus affect the basic nature of amines. Alkyl amines are found to be stronger bases than ammonia. Amines being basic in nature, react with acids to form salts. Aryldiazonium salts, undergo replacement of the diazonium group with a variety of nucleophiles to produce aryl halides, cyanides, phenols and arenes. Answer the following questions :
(a)
How can you convert the following ?
(i)
Ethanoic acid to methanamine
(ii)
Propanenitrile to $\displaystyle 1$-aminopropane
(b)
Why is $\displaystyle \mathrm{pK}_{\mathrm{b}}$ value of aniline more than that of methylamine ?
(c)(i)
Arrange the following in increasing order of their basic strength in aqueous solution : $\displaystyle \mathrm{CH}_{3}-\mathrm{NH}_{2}, \quad\left(\mathrm{CH}_{3}\right)_{2} \mathrm{NH}, \quad\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~N}$
OR
(c)
(ii)
Give the structures of A and B in the following reaction : $\displaystyle \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2} \xrightarrow{\mathrm{Fe} / \mathrm{HCl}} \mathrm{A} \xrightarrow[273 \mathrm{~K}]{\mathrm{HNO}_{2}} \mathrm{~B}$
Marking-scheme solution
(a)(i)
(ii)(b)
Aniline undergoes resonance and as a result the electrons on the N-atom are less
available for donation.
(c)(i)
(CH3)3N < CH3NH2< (CH3)2NH
(c)
(ii)
A= C6H5NH2 ; B= =C6H5N2+Cl
More from Amines
- Assertion: Acetanilide ( -NHCOCH_3 ) is less basic than aniline. Reason (R): Acetylation of aniline results in decrease of electron density on…2024 · asked 2×
- Among the following, which is the strongest base?2023 · asked 2×
- Which of the following is least basic?2023
- Assertion: Aliphatic primary amines can be prepared by Gabriel phthalimide synthesis. Reason (R): Alkyl halides undergo nucleophilic substitution…2024
- How will you obtain the following from benzene diazonium chloride? Write chemical equations involved: 3 []2026
- A compound 'A' on reduction with iron scrap and hydrochloric acid gives compound 'B' with molecular formula C_6 H_7 N. Compound 'B' on reaction with…2022
- Assertion: Aniline is a stronger base than ammonia. Reason (R): The unshared electron pair on nitrogen atom in aniline becomes less available for…2024
- Identify the primary amine from the given options:2024
CBSE Class 12 Chemistry past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.