欲配制与血浆pH相同的缓冲溶液,应选用下列哪一组缓冲对( )
A. HAC-NaAc(pKa=4.75)
B. NaH2PO4-Na2HPO4(pKa=7.20)
C. NH3-NH4Cl(pKa =9.25)
D. H2CO3-NaHCO3(pKa=6.37)
查看答案
人体血浆中最主要的抗碱成分是( )
A. H2PO4-
B. HCO3-
C. HPO42-
D. H2CO3
0.2 mol/L HAc与0.1mol/L NaOH溶液等体积混合后,溶液中的抗酸成分是( )
A. NaOH
B. Ac-
C. HAc
D. OH-
3. A: Something urgent has come up. Could I postpone our appointment?B：_________________________________________
A. sorry, I’ve got an appointment at 8:30 with Mr. Anderson, the bank manager.
B. Ok. Can we see at 2 clock this afternoon?
C. One moment, please.
D. I look forward to meeting you then.
4. A: Do you think theDr. Johnsoncould see me this afternoon?
A. _______________________________________
B. I don’t know.
C. I’d like to cancel my appointment with doctor.
D. I'm afraid Dr. Johnson is occupied this afternoon.
E. I'm afraid there's nothing availavle before noon.
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