Assertion-Reason Questions on Amines
Questions : In the following questions, two statements are given—one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
(a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
(b) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A).
(c) Assertion (A) is correct, but Reason (R) is incorrect statement.
(d) Assertion (A) is incorrect, but Reason (R) is correct statement.
1. Assertion (A) : Hoffmann’s bromamide reaction is given by primary amines.
Reason (R) : Primary amines are more basic than secondary amines.
2. Assertion (A) : In order to convert R–Cl to pure R–NH2, Gabriel-phthalimide synthesis can be used.
Reason (R) : With proper choice of alkyl halides, phthalimide synthesis can be used to prepare 1°, 2° or 3° amines.
3. Assertion (A) : Aromatic primary amines cannot be prepared by Gabriel phthalimide synthesis.
Reason (R) : Aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.
4. Assertion (A) : Butan-1-ol is more soluble in water than butan-1-amine.
Reason (R) : Alcohols are less polar than amines.
5. Assertion (A) : Only a small amount of HCl is required in the reduction of nitro compounds with iron scrap and HCl in the presence of steam.
Reason (R) : FeCl2 formed gets hydrolysed to release HCl during the reaction.
6. Assertion (A) : Acetanilide is less basic than aniline.
Reason (R) : Acetylation of aniline results in decrease of electron density on nitrogen.
7. Assertion (A) : Acylation of amines gives a monosubstituted product whereas alkylation of amines gives polysubstituted product.
Reason (R) : Acyl group sterically hinders the approach of further acyl groups.
8. Assertion (A) : In strongly acidic solutions, aniline becomes more reactive towards electrophilic reagents
Reason (R) : The amino group being completely protonated in strongly acidic solution, the lone pair of electrons on the nitrogen is no longer available for resonance.
9. Assertion (A) : Reduction of m-dinitrobenzene with ammonium sulphide gives m-nitroaniline.
Reason (R) : m-nitroaniline formed gets precipitated and hence further reduction is prevented.
10. Assertion (A) : N-Ethylbenzene sulphonamide is soluble in alkali.
Reason (R) : Hydrogen attached to nitrogen in sulphonamide is strongly acidic.
11. Assertion (A) : N, N-Diethylbenzene sulphonamide is insoluble in alkali.
Reason (R) : Sulphonyl group attached to nitrogen atom is strong electron withdrawing group.
1. (a) 2. (c) 3. (a) 4. (c) 5. (d) 6. (d) 7. (c) 8. (d) 9. (c) 10. (d) 11. (b)