The K_b of ammonia is 1.76 × 10^-5. The pH of a buffer prepared by combining 50.0 mL of 1.00 M ammonia and 50.0 mL of 1.00 M ammonium nitrate is __________. A)4.632 B)9.246 C)4.742 D)9.372 E)none of the above

Question

Quizplus · Accepted Answer

The buffer solution consists of ammonia (NH3) and ammonium ion (NH4+). Using the Henderson-Hasselbalch equation, pH = pKa + log([base]/[acid]). The pKa is calculated from pKb using the relation pKa + pKb = 14. The concentrations of NH3 and NH4+ are equal, so the pH is approximately equal to the pKa, which is 9.246.

The Kb of Ammonia Is 1

The K_b of Ammonia Is 1