Question

Calculate the pH of two buffer systems to compare the differences in pH. One contains 1.0 M NH3 and 3.0 M NH4Cl. (Ka of NH4+, is 5.6x10^-10). The other contains 1.0 M NH3 and 5.0 M NH4Cl. (Ka of NH4+, is 5.6x10^-10).

Answer 1

It's just a matter of substituting into the Henderson-Hasselbalch equation.
pH = pKa + log[(base)/(acid)]
Convert Ka to pKa by pKa = -log Ka

Answer 2

Thank you!