A buffer solution is prepared in which the concentration of NH3 is 0.30 M and the concentration of NH4+ is 0.20 M. If the equilibrium constant, Kb for NH3 equals 1.8 x 10-5, what is the pH of this solution? (log 2.7 = 0.43)
(a) 9.08
(b) 9.43
(c) 11.72
(d) 8.73
