Arrange the following bases in decreasing order of basicity is (i) Aniline (ii) O - nitroaniline (iii) m- nitroaniline (iv) p - nitroaniline

Step-by-step solution

Basicity is directly proportional to the + M , + I effect, but it is inversely proportional to the - M , - I effect. Aniline is the highest basic because it does not have any group. But the nitro group can show the - I   and - M effect. The nitro group at meta position show only the - I effect. But at ortho and para position, it will show the - M , - I effect both. So, the m - nitroaniline is more basic than the p - nitroaniline and o - nitroaniline. So, the basicity order is :- Hence, the decreasing order of