What is the pH of an aqueous solution composed of 0.64 M NH₄⁺ and 0.20 M NH₃? (K_a of NH₄⁺ = 5.6 $\times$ 10^-10) A) 4.80 B) 8.75 C) 9.20 D) 9.25 E) 9.76

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Quizplus · Accepted Answer

The solution is a buffer composed of NH4+ (acid) and NH3 (base). Use the Henderson-Hasselbalch equation: pH = pKa + log([base]/[acid]). pKa = -log(Ka) = 9.25. pH = 9.25 + log(0.20/0.64) = 8.75.

What Is the PH of an Aqueous Solution Composed of 0.64