Q. Which of the following is the strongest base in aqueous solution?
Answer: Diethylamine
Notes: Amines are organic derivatives of ammonia, in which one, two, or all three of the hydrogens of ammonia are replaced by organic groups. All aliphatic primary amines are stronger bases than ammonia. In aqueous solution, the pKb’s (basicity) of ammonia, methyl amine, dimethylamine, and trimethyl amine are therefore, respectively, 4.74, 3.34, 3.27. and 4.19. In terms of pKb, the strongest bases have the least positive values of pKb. So in aqueous solutions, the strongest bases are:

• Dimethylamine > Methylamine > trimethylamine > Ammonia.