单项选择题
A.V(NaOH)=V(KMnO4) B.3V(NaOH)=4V(KMnO4) C.4×5V(NaOH)=3V(KMnO4) D.4V(NaOH)=5×3V(KMnO4)
A.Na2CO3 B.2Na2CO3 C.1/3Na2CO3 D.1/2Na2CO3
A.HAc(Ka=1.8×10-5)-NaAc B.HAc-NH4Ac C.NH3·H2O(Kb=1.8×10-5)-NH4Cl D.KH2PO4-Na2HPO4