问题详情

要配制pH=4.0的缓冲溶液，应选用( )
A． NaH2PO4-Na2HPO4(pK(H2PO4-)=7.21)

B．HAc-NaAc(pK(HAc)=4.76)
C．HCOOH-HCOONa(pK(HCOOH)=3.75)

D．NH3-NH4Cl (pK(NH3)=4.75)