Match List I with List II
List I (Amines)                List II (pKb)
A. Aniline                           I. 3.25
B. Ethanamine                II. 3.00
C. N-Ethylethanamine         III. 9.38
D. N,N-Diethylethanamine   IV. 3.29
Choose the correct answer from the options given below:-

We need to match each amine with its correct $$pK_b$$ value. From NCERT data the $$pK_b$$ values of common amines are: aniline ($$C_6H_5NH_2$$, primary aromatic) $$pK_b = 9.38$$; ethanamine ($$C_2H_5NH_2$$, primary aliphatic) $$pK_b = 3.29$$; N-ethylethanamine ($$(C_2H_5)_2NH$$, secondary aliphatic) $$pK_b = 3.00$$; and N,N-diethylethanamine ($$(C_2H_5)_3N$$, tertiary aliphatic) $$pK_b = 3.25$$.

List II gives I = 3.25, II = 3.00, III = 9.38, and IV = 3.29. Aniline $$\rightarrow$$ III ($$pK_b = 9.38$$) because resonance with the benzene ring weakens its basicity. Ethanamine $$\rightarrow$$ IV ($$pK_b = 3.29$$) as a primary aliphatic amine. N-ethylethanamine $$\rightarrow$$ II ($$pK_b = 3.00$$) since the +I effect of two alkyl groups and minimal steric hindrance makes it the strongest base here. N,N-diethylethanamine $$\rightarrow$$ I ($$pK_b = 3.25$$) because steric effects in the tertiary amine reduce its basicity compared to the secondary amine.

The complete matching is A-III, B-IV, C-II, D-I, so the correct answer is Option D.