Question

What is the decreasing order of basicity of 1$^{\circ}$, 2$^{\circ}$ and 3$^{\circ}$ ethyl amines and ammonia?

• A. $NH_3 > C_2 H_5 NH_2 > (C_2 H_5)_2 NH > (C_2 H_5)_3 N$
• B. $(C_2 H_5)_3 N > (C_2 H_5)_2 NH > C_2 H_5 NH_2 > NH_3$
• C. $(C_2 H_5)_2 NH > C_2 H_5 NH_2 > (C_2 H_5)_3 N > NH_3$
• D. $(C_2 H_5)_2 NH > (C_2 H_5)_3 N > C_2 H_5 NH_2 > NH_3$

Answer 1

Answer: (D)

$(C_2 H_5)_2 NH > (C_2 H_5)_3 N > C_2 H_5 NH_2 > NH_3$

Answer 2

As the number of alkyl groups increases, the electron density on nitrogen atom also increases, so the basic character increases but 3$^{\circ}$
amines are less basic than 2$^{\circ}$ amines due to steric hindrance of 3$^{\circ}$ amines, so the correct order of basicity is \hspace15mm Ammonia < 1 $^{\circ}$ < 3$^{\circ}$ < 2$^{\circ}$ $NH_3 < C_2 H_5 NH_2 < (C_2H_5)_3 N < (C_2 H_5)_2 NH$