Question
Arrange the following in the decreasing order of their basic strength in aqueous solutions:
CH3NH2, (CH3)2NH, (CH3)3 N and NH3
Solution
With the increase in alkyl group, the +I effect will increase which will increase the ease of donation of lone pair electron .But in water one other factor is controlling the strength of basicity. Amine will accept a proton and from cation will be stabilised in water by salvation (by hydrogen bonding).better the salvation by hydrogen bonding higher will be the basic strength.
(CH3)2 NH > CH3 NH2 > (CH3)3 N > NH3
