Given the chemical tests to distinguish between the following pairs of compounds :
(i) Methylamine and Dimethylamine
(ii) Aniline and N - Methylamine

Explanation

(i) Ethylamine and Dimethylamine : Methylamine and Dimethylamine : They can be distinguished by carbylamine test. When heated with alcoholic solution of KOH and chloroform, methylamine gives foul smell of methyl isocyanide .
`CH_(2) NH_(2) + CHCl_(3) + 3 KOH to underset("isocyanide (foul smell)")underset("Methyl")(CH_(3) NC) + 3KCl + 3 H_(2) O `
Dimethylamine does not give carbylamine test
`underset("Dimethylamine")((CH_(3))_(2)NH) overset(CH Cl_(3), KOH) to "No reaction"`
(ii) Aniline and N-methylaniline : Warm each compound separately with few drops of chloroform and alcoholic KOH . Amiline (primary amine) gives offensive smell of isocyanide while N-methyl aniline (secondary amine ) does not give carbyl amine test.
`C_(6)H_(5) NH_(2) +CH_(3) Cl+ 3KOH (Alc) overset(Delta) to underset(("carbyl amine")) (C_(6) H_(5) NC)+3KCl + 3H_(2) O`