Give the chemical tests to distinguish between the following pairs of compounds :
(i) Ethylamine and Aniline
(ii) Aniline and Benzlamine

Explanation

(i) Ethylamine and Aniline : Ethylamine with `NHO_(2)(NaNO_(2)+"dil"CHl)` at 273 - 278 K give a brish evolution of `N_(2)` gas with the formation of primary atcohls.
`underset("Ethylamine")(C_(2)H_(5)NH_(2))+HONO overset(273-278K)to underset("Ethylalcohol")(C_(2)H_(5)-OH)+N_(2)+H_(2)O`
Aniline with `HNO_(2)` at 273 - 278 K followed by treatment with an alkaline solution of 2-naphthol when a brilliant yellow, orange or red coloured dye is obtained.


(ii) Aniline and Benzylamine : Benzylamine reacts with nitrous acid to form a diazonium salt which is unstable at low temperature, decomposes with evolution of `N_(2)` gas
`underset(" Benzyl alcohol")(C_(6)H_(5)CH_(2)NH_(2))underset(HCl)overset(HONO)to[C_(6)H_(5)CH_(2)-N^(+)underset("unstable")-=NCl^(-)]overset(H_(2)O)toC_(6)H_(5)CH_(2)underset("HCl")underset(+)(O)H+N_(2)uparrow+ HCl`
Aniline reacts with `HNO_(2)` to form benzene diazonium Chloride which is stable at 273 - 278 K and hence does not decompose to evolve `N_(2)` gas