At 25 ^$\circ$C, the base ionization constant for NH₃ is 1.8 * 10^-5. Determine the pH of a solution prepared by adding 0.0500 mol of solid ammonium chloride to 100. mL of 0.150 M ammonia.

Question

Quizplus · Accepted Answer

The solution is a buffer consisting of NH₃ and NH₄Cl. Use the Henderson-Hasselbalch equation: pH = pKa + log([base]/[acid]). Calculate pKa from pKb: pKa = 14 - pKb = 9.26. [NH₃] = 0.150 M, [NH₄⁺] = 0.500 M. pH = 9.26 + log(0.150/0.500) = 8.73.

At 25 ∘\circ∘ C, the Base Ionization Constant for NH3 Is 1

At 25 ^$\circ$C, the Base Ionization Constant for NH₃ Is 1