Arrange the following compounds in increasing (weakest to strongest) order of basicity.
A) IV

Question

Arrange the following compounds in increasing (weakest to strongest) order of basicity. 
A) IV < II < I < III 
B) III < II < IV < I 
C) II < I < III < IV 
D) II < III < I < IV 
E) None of the above

Quizplus · Accepted Answer

Basicity depends on the availability of lone pair electrons on the nitrogen atom. In compound I, nitrogen is bonded to a carbonyl group which draws electrons away from the nitrogen atom, making the lone pair less available for protonation. In compound IV, nitrogen is in a pyridine ring which enhances the availability of the lone pair, making it the most basic. Therefore, the increasing order of basicity is II < I < III < IV, which is only provided by choice C.

Arrange the Following Compounds in Increasing (Weakest to Strongest) Order