Ammonium (NH3) has Kb = 1.8 x 10–5. What is the pH of a solution that contains the molar ratio of the base-to-conjugate acid: [NH3]/[NH4+] = 1/3

Answer 1

Buffer solution (weak base + conjugate acid)

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

pKb = -log 1.8x10-5 = 4.74

[conj.acid]/[base] = 3/1

pOH = 4.74 + log 3

pOH = 4.74 + 0.477

pOH = 5.22

pH = 14 - 5.22

pH = 8.8