此缓冲溶液的计算公式为:[OH-] = Kb [NH3]/ [NH4 +] [OH-] = 1.76*10^-5 * 0.2 / 0.1pOH = - lg 1.76*10^-5 * 2 = 4.45pH = 14 - 4.45 = 9.55