Chemistry Help!

Question

If a buffer solution is 0.300 M in a weak base (Kb = 7.6x10^-5) and 0.530M in its conjugate acid, what is the pH?

Answer 1

One form of the Henderson Hasselbalch equation for a basic buffer is...

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

pKb = -log Kb = -log 7.6x10^-5 = 4.12

pOH = 4.12 + log (0.530 / 0.300)

pOH = 4.12 + log 1.77

pOH = 4.12 + 0.247

pOH = 4.37

pH + pOH = 14

pH = 14 - pOH

pH = 14 - 4.37

pH = 9.63