We’re being asked to calculate the pH of a solution that is 0.24 M NH_{3} and 0.16 M NH_{4}Cl

In this case, we will be using the Henderson-Hasselbalch equation which can be used for buffer solutions

Recall the Henderson-Hasselbalch equation:

$\overline{){\mathbf{pH}}{\mathbf{=}}{{\mathbf{pK}}}_{{\mathbf{a}}}{\mathbf{+}}{\mathbf{log}}\left(\frac{\mathbf{conjugate}\mathbf{}\mathbf{base}}{\mathbf{weak}\mathbf{}\mathbf{acid}}\right)}$

A buffer solution is prepared that is 0.24 M NH_{3} and 0.16 M NH_{4}Cl. What is the pH of this buffer?

K_{b} for NH_{3} is 1.8 x 10^{-5}

a. 10.22

b. 9.43

c. 8.78

d. 9.82

e. 10.62