Question

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

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

Answer 1

(i) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide:

Due to the +I effect of −CH₃ group, methylamine is more basic than water. Therefore, in water, methylamine produces OH⁻ ions by accepting H⁺ ions from water. 

Ferric chloride (FeCl₃) dissociates in water to form Fe³⁺ and Cl⁻ ions.

Then, OH⁻ ion reacts with Fe³⁺ ion to form a precipitate of hydrated ferric oxide. 

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

Nitration is carried out in an acidic medium. In an acidic medium, aniline is protonated to give anilinium ion (which is meta-directing). 

For this reason, aniline on nitration gives a substantial amount of m-nitroaniline.