Question

Choose the strongest base among the following:

• A. ¯CH₂-CH₂-NH₂
• B. ¯CH₂ -CH = CH₂
• C. ¯CH₂-C ≡ N
• D. ¯CH₂ - C ≡ CH

Answer 1

Answer: (A)

¯CH₂-CH₂-NH₂

Answer 2

In carbanions, stronger bases have their negative charge less stabilized by resonance or inductive effects.

• (B) and (C) are resonance/stabilized (allylic and cyano respectively) and (D) is stabilized due to the high s-character of the sp carbon in the alkyne group.
• In (A), the -NH₂ group is electron donating (by +I effect) which does not stabilize the negative charge through resonance, making the carbanion more reactive and thus the strongest base.