What is the pH of a buffer system prepared by dissolving 10.70 grams of NH₄Cl and 25.00 mL of
12 M NH₃ in enough water to make 1.000 L of solution? K_b = 1.80 × 10^-5for NH₃.

Question

Quizplus · Accepted Answer

The pH of the buffer can be calculated using the Henderson-Hasselbalch equation. First, calculate the concentrations of NH₄⁺ and NH₃. The concentration of NH₄⁺ is 0.200 M (from 10.70 g NH₄Cl in 1 L), and the concentration of NH₃ is 0.300 M (from 25 mL of 12 M NH₃ in 1 L). Using the equation pH = pKa + log([base]/[acid]), where pKa = 14 - pKb, the pH is approximately 9.43.

What Is the PH of a Buffer System Prepared by Dissolving