Arrange the following compounds in the decreasing order of their basic strength: (I) 4 -nitroaniline (II) 3 -nitroaniline (III) 3 -methoxyaniline (IV) 4 -methoxyaniline

Step-by-step solution

Basic strength of anilines depends on the availability of the lone pair of electrons on the nitrogen atom for protonation. Electron donating groups (EDG) increase basicity, while electron withdrawing groups (EWG) decrease it. In (IV) 4 -methoxyaniline, the -OCH₃ group is at the para position. It exerts a strong +M effect which dominates over its -I effect, increasing the electron density on the nitrogen atom and making it the most basic. In (III) 3 -methoxyaniline, the -OCH₃ group is at the meta position where the