Account for the following:
(i) $p K_{b}$ of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

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Solution

(i) $p K_{b}$ of aniline is more than that of methylamine.
In aniline, the lone pair of electrons on $N$ atom is in resonance with benzene ring. Hence, it cannot be easily donated to an acid. This decreases its basicity. In methyl amine, the $+ I$ effect of methyl group increases the electron density on $N$ atom so that the lone pair of electrons on $N$ atom can be easily donated to an acid. Hence, methylamine is more basic than aniline. Higher is the basicity, lower is the $p K b$ and vice versa.

(ii) Ethylamine is soluble in water whereas aniline is not. With increase in the molecular weight, the solubility decreases. Aniline has higher molecular weight than ethylamine.

(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide. Due to the $+ I$ effect of $- C H_{3}$ group, methylamine is more basic than water. Therefore, in water, methylamine produces $O H^{-}$ ions by accepting $H^{+}$ ions from water. $O H^{-}$ ions react with ferric chloride to precipitate hydrated ferric oxide.

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Account for the following:

(i) pK_bof aniline is more than that of methylamine.

(ii) Ethylamine is soluble in water whereas aniline is not.

(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

(iv) Although amino group is o, p− directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.

(v) Aniline does not undergo Friedel-Crafts reaction.

(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines.

(vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.

Account for the following

(i) $p K_{b}$ of aniline is more than that of methyl amine.

(ii) Ethylamine is soluble in water whereas aniline is not

(iii) Methyl amine in water reacts with ferric chloride to precipitate hydrated ferric oxide

(iv) Although amino group is o- and p- directing in aromatic electrophilic substitution, aniline on nitration gives a substantial amount of m-nitroaniline

(v) Aniline does not undergo Friedel Crafts reaction

(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines

(vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines

Q. Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

Which among the following are the correct statements?

Statement 1: Methyl-amine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

Statement 2: Methylamine is more basic than ammonia.

Q. Ethylamine is not soluble in water whereas aniline is.
If this is true enter 1, if false enter 0.

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Account for the following:(i) pKb of aniline is more than that of methylamine.(ii) Ethylamine is soluble in water whereas aniline is not.(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

Account for the following:
(i) $p K_{b}$ of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.