单项选择题
A.HAc(Ka=1.8×10-5)-NaAc B.HAc-NH4Ac C.NH3·H2O(Kb=1.8×10-5)-NH4Cl D.KH2PO4-Na2HPO4
A.1mol/LHAc B.1mol/LHAc和0.5mol/LNaAc C.1mol/LNH3 D.1mol/LNH4Cl