KEAM 2014 Physics and Chemistry Paper

More the availability of N -atom to donate its lone pair, more will be basicity of amine.
Thus, presence of electron releasing groups (like −CH3,−C2H5 ) increases the basicity but presence of electron withdrawing group (Like −C6H5 ) decreases the basicity. Ammonia (NH3) because of the absence of any group is less basic than the amines having electron releasing group. Thus, the order of basic strength of the given compounds is
(because of two electron releasing −CH3 group)