Give reasons for any 3 of the following observations: 
(a) Explain why an alkylamine is more basic than ammonia? 
(b) pKb value for aniline is more than that for methylamine. 
(c) Ethylamine is soluble in water whereas aniline is not soluble in water. 
(d) Primary amines have higher boiling points than tertiary amines.

(A) Due to electron releasing inductive effect (+1) of alkyl group, the electron density on the nitrogen atom increases and thus, it can donate the lone pair of electrons more easily than ammonia. 

(B) Higher the pKb value, lower will be the basicity therefore aniline is less basic than methylamine because the lone pair of electrons on nitrogen atom gets delocalized over the benzene ring are unavailable for protonation due to resonance in aniline which is absent in case of alkylamine.

(C) Ethylamine is soluble in water due to its capability to form H-bonds with water while aniline is insoluble in water due to larger hydrocarbon part which tends to retard the formation of H-bonds. 

(D) Due to presence of two H-atoms on N-atom of primary amines, they undergo extensive intermolecular H-bonding while tertiary amines due to the absence of a H-atom on the N-atom, do not undergo H- bonding. As a result, primary amines have higher boiling points than 3° amines.