Determine the pH of a buffer that is 0.25 M NH₃ and 0.15 M NH₄Cl. The value of pKb for NH₃ is 4.75.

Answer 1

Henderson Hasselbalch equation:

pOH = pKb + log [conj.acid]/[base]

pOH = 4.75 + log [0.15]/[0.25]

pOH = 4.75 + (-0.22)

pOH = 4.53

pH = 14 - 4.53

pH = 9.47