Due to −R effect of the C=O group the electron density on the N -atom decreases, hence amides are weaker base than NH3 and aliphatic amines. Further due to -1 effect of NH2 group, the electrondensity on the other N -atom decreases. As a result, NH2NH2 is a much weaker base than NH3 and aliphatic amines. Therefore, ethylamine is most basic among these.