Question

i'd like to know why dimethylamine is a stronger base than trimethylamine even though there are 3 CH3 groups in the latter ?

Answer 1

Trimethyl amine is weaker base than dimethyl amine because in case of trimethyl amine lone pair of nitrogen are sterically hindered by presence of three bulkier methyl group. Here the electron releasing effect of methyl group is sacrificed by the steric hinderance. Due to steric hinderance, lone pair of electrons are not easily available to donate hence trimethylamine is weaker base than dimethyl amine