(i) Aliphatic amines are more basic than aromatic amines. Therefore CH3CH2NH2and CH3NH2 are more basic. Among the ethylamine and methylamine, ethylamine was experienced more +1 effect than methylamine and hence ethylamine is more basic than methylamine.
(ii) Nitrogroup has a powerfol electron withdrawing group and they have both -R effect as well as -I effect. As a result, all the nitro anilines are weaker bases than aniline. In P-nitroaniline
both R effect and -I effect of the NO2 group decrease the basicity.
(iii) Therefore decreasing order of basic strength is,
