Answer:
(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.
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Answer is: Louis Pasteur (1822-1895) disproved spontaneous generation. He boiled liquid with proteins and other nutrients in S-neck flasks and regular flask to kill all microorganism present. In regular flask liquid showed changes when exposed to air and in S-neck flack there was no change (microorganism can not getting in the flask because the S- neck). When he removed S-neck, liquid changed because microorganisms came in liquid.
Pasteur showed it was not the air itself but particles within the air that had microorganisms.
They all have the same number of electrons in their outer shell.