Organic Compounds Containing Nitrogen Test - 12

The basicity of o-, m- and p-toluidines decreases in the order p > m > o. In other words, their pK_b values will increase in the reverse order, i.e. option (1) is correct, i.e. p < m < o.

Both 2, 4-dimethylaniline and p-methylbenzylamine are 1^o amines and hence, give carbylamine test.

Primary amines form benzenesulphonamides which are soluble in alkali solutions, i.e.

In spite of the dipolar structure, sulphanilic acid is insoluble in water probably due to the large hydrocarbon part.

Electron-donating groups increase the stability of diazonium cations by dispersing the +ve charge on the N-atom.

Sandmeyer reaction on p-chloroaniline gives p-dichlorobenzene which is a solid (m.p. 325 K) while that on anilinium chloride gives chlorobenzene which is a liquid (b.p. 405 K).

Further, anilinium hydrochloride is an acid salt and hence, liberates CO₂ from NaHCO₃ and gives white ppt. of AgCl with AgNO₃ solution.

p-chloroaniline is neither acidic (actually it is basic) nor contains an ionic chloride and hence, does not give the above reactions. Thus, options (1), (3) and (4) are correct. However, both p-chloroaniline and anilinium hydrochloride, being 1^o amines, give carbylamine test.