The correct increasing order of basic strength for the following compounds is _________.

(I)

(II)

(III)

• p-toluedene (III) is the strongest base among the 3 given compounds because the presence of −CH₃ group in the p position, which has electron-donating (+I effect) that increases the electron density on the N-atom atom and make the electron pairs more available for protonation.

• In case of I and II aniline is moe basic than III p-nitroaniline; but aniline is less basic than III p- toluedene.

• p-nitroaniline there is a nitro group in the ‘para’ position of the benzene ring which is an electron-withdrawing group and involves the lone pair on N atom in resonance thus decreasing its ability to donate unshared electron pairs to acid.

• In case of aniline the conjugation is not as effective as p-nitroaniline so it is a better base.