Question

The tertiary amines are less basic than secondary amines because :

• A. Do not have enough alkyl group
• B. Alkyl group causes crowding
• C. They have many lone pair of electrons
• D. The above statement is wrong

Answer 1

The correct option is B Alkyl group causes crowding

The tertiary amines are less basic than secondary amines. The reason is that a tertiary amine, though has three alkyl groups which can donate electrons to the nitrogen atom but they also cause crowding (also called steric hinderance) around nitrogen. This hinders the protonation at nitrogen atom and hence, reduces the basicity.