The pH of aqueous 0.10 M pyridine (C₅H₅N)ion is 9.09.What is the K_b of this base?

Question

Quizplus · Accepted Answer

The pKa of pyridine is 5.25. Therefore, the Kb of pyridine can be calculated as follows:

Kw = Ka x Kb 
1.0 x 10^-14 = 5.7 x 10^-6 x Kb 
Kb = 1.5 x 10^-9

Now, we can use the Kb equation to calculate the concentration of hydroxide ions:

Kb = [OH-][C5H5N]/[C5H5NH+] 
1.5 x 10^-9 = [OH-][0.10]/[0.90] 
[OH-] = 1.5 x 10^-8

Finally, we can use the concentration of hydroxide ions to calculate the pH:

pH = 14 - pOH = 14 - (-log[OH-]) = 14 - (-log(1.5 x 10^-8)) = 9.09

Therefore, the answer is B, 1.5 x 10^-9.

The PH of Aqueous 0 ×\times× 10-10 B) 1 ×\times× 10-9 C) 9