What is the pH of a 0.470 M solution of pyridine? Kb = 1.5 × 10^-9 A) 9.6 B) 11.2 C) 2.8 D) 9.4 E) 4.6

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Quizplus · Accepted Answer

The correct answer is D because the pH of a 0.470 M solution of pyridine can be calculated using the Kb value of pyridine and the equation pH = 14 - pOH. The pOH can be calculated using the equation pOH = -log[OH-], where [OH-] is the hydroxide ion concentration. The hydroxide ion concentration can be calculated using the Kb value and the equation Kb = [OH-][C5H5NH+][C5H5N]. The concentration of C5H5NH+ can be calculated using the equation [C5H5NH+] = [C5H5N] - [OH-]. Substituting all of these equations into the equation for pH gives pH = 14 - (-log[OH-]) = 14 - (-log(Kb[C5H5N]/[C5H5NH+])) = 14 - (-log(1.5 × 10^-9 * 0.470 M / (0.470 M - [OH-]))) = 9.4.

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