Chemistry Reference
In-Depth Information
7. Which proton is the least acidic? Explain your answer.
The pK
a
value associated with carboxylic acid is approximately 4.75. The pK
a
value of a
primary alcohol is approximately 16. The pK
a
value of an amine is approximately 35.
The pK
a
value of a protonated amine is approximately 10. Since the highest pK
a
value belongs to the amine, protons associated with the amine functionality are the
least acidic.
8. Separate the following group of bases into a group of hard bases and a group of soft
bases. Rationalize your answers based on electronegativity and polarizability.
As a general rule, the basic atoms associated with soft bases have lower electronegativ-
ities and are more polarizable. Likewise, the basic atoms associated with hard bases
have higher electronegativities and are less polarizable. Therefore, using the periodic
table of the elements, the group of bases listed above can be separated as illustrated.
