JEE Main 2013 — Amines Question with Solution

The correct order of relative basicity of amines in the gas phase is $3^{\circ }>2^{\circ }>1^{\circ }>{\mathrm{NH}}_3$ The alkyl group releases electron and thus, tends to disperse the positive charge of the alkyl ammonium ion and therefore stabilises it. Since, ${\mathrm{NH}}_4{}^{+}$(from ${\mathrm{NH}}_3$ ) has no such alkyl group, it is not stabilised to such an extent as alkylammonium ion.