Which of the following is least basic . ?

Options

A. o-Anisidine
B. p-Anisidine
C. m-Anisidine
D. Aniline

Answer

C

Explanation

Methoxy `(CH_(3O))` group of anisidine is strongly electron donating fron the ortho and para positions by extended `pi` bonding This effect completely dominates the electron -withdrawing inductive effect form these positions Therefore we expect o-and p-anisidines to be stronger bases than anline but hte correct order of basicity is p-Anisidine gtaniline gt o-Anisidine o-Anisidine is weaker than aniline on account of ortho effect All o-substituted anilines are less basic than p-substitude anilines regrrdless of the electronic effect of the substituent THis effect is attributed to stric hindrance by the o-substituent to solvation of the cation This steric effect destabilizes the cation making the amine a weaker base m-Anisidine is the cation making the amine a weaker base m-Anisidine is the weakest base because `m-CH_(3)O` group is electron withdrawing in nature on account of -I effect Note the there is no resonance effect at the meta position .