Question

Amines are usually formed from amides, imides, halides, nitro compounds, etc. They exhibit hydrogen bonding which influences their physical properties. In alkyl amines, a combination of electron releasing, steric and H-bonding factors influence the stability of the substituted ammonium cations in protic polar solvents and thus affect the basic nature of amines. Alkyl amines are found to be stronger bases than ammonia. Amines being basic in nature, react with acids to form salts. Aryldiazonium salts, undergo replacement of the diazonium group with a variety of nucleophiles to produce aryl halides, cyanides, phenols and arenes.

Arrange the following in increasing order of their basic strength in aqueous solution:
CH$_3$–NH$_2$, (CH$_3$)$_2$NH, (CH$_3$)$_3$N

Hint:

The basicity of amines increases with the number of alkyl groups attached to nitrogen as they donate electrons, enhancing the availability of the lone pair for protonation.

Answer 1

The order of basic strength in aqueous solution is determined by the electron-donating effect of the alkyl groups on nitrogen. The more alkyl groups attached to nitrogen, the stronger the base due to increased electron density. The correct order is:
(CH$_3$)$_3$N>(CH$_3$)$_2$NH>CH$_3$–NH$_2$