13.11 Give one chemical test to distinguish between the following pairs of compounds.

(i) Methylamine and dimethylamine

(ii) Secondary and tertiary amines

(iii) Ethylamine and aniline

(iv) Aniline and benzylamine

(v) Aniline and N-methylaniline. 

The best test for distinguishing methyl amine and dimethylamine is the Carbylamines test.

Carbylamine Test: Aliphatic and aromatic primary amines on heating with chloroform and ethanolic potassium hydroxide form foul-smelling isocyanides or carbylamines.

In this case, Methylamine (which is an aliphatic primary amine) gives a positive carbylamine test while dimethylamine wont.

Hinsberg's reagent (benzenesulphonyl chloride, C₆H₅SO₂Cl). can be used to distinguish secondary and tertiary amines.

Hinsberg Test: Secondary amines react with Hinsberg's reagent to form a product that is insoluble in an alkali. For example, N, N? diethylamine reacts

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The best test for distinguishing methyl amine and dimethylamine is the Carbylamines test.

Carbylamine Test: Aliphatic and aromatic primary amines on heating with chloroform and ethanolic potassium hydroxide form foul-smelling isocyanides or carbylamines.

In this case, Methylamine (which is an aliphatic primary amine) gives a positive carbylamine test while dimethylamine wont.

Hinsberg's reagent (benzenesulphonyl chloride, C₆H₅SO₂Cl). can be used to distinguish secondary and tertiary amines.

Hinsberg Test: Secondary amines react with Hinsberg's reagent to form a product that is insoluble in an alkali. For example, N, N? diethylamine reacts with Hinsberg's reagent to form N,

N? diethylbenzenesulphonamide, which is insoluble in an alkali. Tertiary amines, however, do not react with Hinsberg's reagent.

Azo-dye test can be used to distinguish ethylamine and aniline.

Azo-dye test: A dye is obtained when aromatic amines react with HNO₂ (NaNO₂ + dil.HCl) at 0- 5°C, followed by a reaction with the alkaline solution of 2-naphthol. The dye is usually yellow, red, or orange in colour. Aliphatic amines give a brisk effervescence due to the evolution of N₂ gas under similar conditions.

Aniline and benzylamine can be distinguished with the help of nitrous acid.

Nitrous acid test: Benzylamine reacts with nitrous acid to form unstable diazonium salt, which in turn gives alcohol with the evolution of nitrogen gas, while aniline reacts with nitrous acid to form a stable diazonium salt without releasing nitrogen gas.

Carbylamine test can be used to distinguish between Aniline and N-methylaniline.

Carbylamine Test: Primary amines, on heating with chloroform and ethanolic potassium hydroxide, form foul smelling isocyanides or carbylamines. Aniline, being an aromatic primary

amine, gives positive carbylamine test. However, N-methylaniline, being a secondary amine does not.

 

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<p>The best test for distinguishing methyl amine and dimethylamine is the Carbylamines test.</p><p><u>Carbylamine Test</u>: Aliphatic and aromatic primary amines on heating with chloroform and ethanolic potassium hydroxide form foul-smelling isocyanides or carbylamines.</p><p>In this case, Methylamine (which is an aliphatic primary amine) gives a positive carbylamine test while dimethylamine wont.</p><div><div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1687506391php8c8qKF_480x360.jpeg" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1687506437php8bpCp5_480x360.jpeg" alt="" width="503" height="115"></picture></div></div><p><u>Hinsberg's reagent (benzenesulphonyl chloride, C₆H₅SO₂Cl).</u> can be used to distinguish secondary and tertiary amines.</p><p><u>Hinsberg Test:</u> Secondary amines react with Hinsberg's reagent to form a product that is insoluble in an alkali. For example, N, N? diethylamine reacts with Hinsberg's reagent to form N, </p><p>N? diethylbenzenesulphonamide, which is insoluble in an alkali. Tertiary amines, however, do not react with Hinsberg's reagent.</p><div><div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1687506437php8bpCp5_480x360.jpeg" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1687506437php8bpCp5.jpeg" alt="" width="" height=""></picture></div></div><p>Azo-dye test can be used to distinguish ethylamine and aniline.</p><p>Azo-dye test: A dye is obtained when aromatic amines react with HNO₂ (NaNO₂ + dil.HCl) at 0- 5°C, followed by a reaction with the alkaline solution of 2-naphthol. The dye is usually yellow, red, or orange in colour. Aliphatic amines give a brisk effervescence due to the evolution of N₂ gas under similar conditions.</p><div><div><picture><source srcset="https://images.shiksha.com/mediadata/images/articles/1687506470php8W7Xfr_480x360.jpeg" media=" (max-width: 500px)"><img src="https://images.shiksha.com/mediadata/images/articles/1687506470php8W7Xfr.jpeg" alt="" width="596" height="271"></picture></div></div><p>Aniline and benzylamine can be distinguished with the help of nitrous acid.</p><p><u>Nitrous acid test</u>: Benzylamine reacts with nitrous acid to form unstable diazonium salt, which in turn gives alcohol with the evolution of nitrogen gas, while aniline reacts with nitrous acid to form a stable diazonium salt without releasing nitrogen gas.</p><p>Carbylamine test can be used to distinguish between Aniline and N-methylaniline.</p><p>Carbylamine Test: Primary amines, on heating with chloroform and ethanolic potassium hydroxide, form foul smelling isocyanides or carbylamines. Aniline, being an aromatic primary</p><p>amine, gives positive carbylamine test. However, N-methylaniline, being a secondary amine does not.</p><div>&nbsp;</div>

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