Calculate the pH of a solution that is 7.22 *10^-⁴ M C₆H₅NH₂. K_b is 3.8 *10^-¹⁰. A) 6.28 B) 7.72 C) 6.50 D) 7.50 E) none of these

Question

Quizplus · Accepted Answer

First, we need to find the concentration of H+ ions in solution using the equation:
pH = -log[H+]
[H+] = 10^(-pH)
[H+] = 10^(-7.22) * 3.8 * 10^(-14)
[H+] = 4.75 * 10^(-22)

Now we can calculate the pOH of the solution using the equation:
pH + pOH = 14
pOH = 14 - pH
pOH = 14 - 7.22
pOH = 6.78

Finally, we can calculate the concentration of OH- ions in solution using the equation:
pOH = -log[OH-]
[OH-] = 10^(-pOH)
[OH-] = 1.78 * 10^(-7)

Now we can use the equation for the ion product constant of water to find the concentration of H+ ions in the solution:
Kw = [H+][OH-]
Kw = (1.00 * 10^-14)
(1.00 * 10^-14) = (4.75 * 10^-22) [OH-]
[OH-] = (1.00 * 10^-14) / (4.75 * 10^-22)
[OH-] = 2.11 * 10^7

Finally, we can use the equation for the ion product constant of water to find the concentration of H+ ions in the solution:
[H+] = (1.00 * 10^-14) / (2.11 * 10^7)
[H+] = 4.74 * 10^-22

Now we can calculate the pH of the solution using the equation:
pH = -log[H+]
pH = -log(4.74 * 10^-22)
pH = 7.72

Therefore, the answer is B) 7.72.

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