A buffer solution is prepared in which the concentration of \(\mathrm{NH}_{3}\) is \(0.30 \mathrm{M}\) and the concentration of \(\mathrm{NH}_{4}^{+}\)is \(0.20 \mathrm{M}\). If the equilibrium constant, \(\mathrm{K}_{\mathrm{b}}\) for \(\mathrm{NH}_{3}\) equals \(1.8 \mathrm{x}\) \(10^{-5}\), what is the pH of this solution? ( \(\log 2.7=0.43\) )
(a) \(9.08\)
(b) \(9.43\)
(c) \(11.72\)
(d) \(8.73\)