Give the correct order of decreasing basicity of the following compounds:
(a) I > II > III > IV (b) IV > III > II > I
(c) IV > I > II> III (d) III > II > I > IV
Basicity decreases due to :
1)Presence of electron withdrawing group
2) delocalization of lone pair on N due to resonance with benzene ring.
In this question
Structure IV --N is bonded to sp3 carbon - No resonance
Structure I --Lone pair are delocalized in phenyl group
Structure II --Lone pair are delocalized in two phenyl groups
Structure III --Lone pair are delocalized in 3 phenyl groups
Now you can arrange them in basicity order