Which of the following bases is the STRONGEST? The base is followed by its Kb. A. C6H5NH2, 4.0 × 10-10 B. NH3, 1.76 × 10-5 C. CH3NH2, 4.4 × 10-4 D. (CH3CH2)2NH, 8.6 × 10-4 E. C5H5N, 1.7 × 10-9

(D) (CH3CH2)2NH

Explanation:

In order to decide which base is strongest we need to calculate its PKb

PKb = -log [Kb]

A large Kb value and small PKb value gives the strongest base

 Compound                   Kb                           PKb      

(A) C6H5NH2 -         4 x 10^-10                      9.349

(B) NH3                     1.76x 10^-5                    4.754

(C) CH3NH2              4.4x 10^-4                     3.357

(D) (CH3CH2)2NH   8.6x 10^-4                     3.066

(E) C5H5N                  1.7x10^-9                      8.77  

Clearly (CH3CH2)2NH is the strongest base.

28528289 29823282 8298232 39858