题目内容

配制pH=9.30的缓冲溶液,下列缓冲对中最合适的是( )

A. NaHCO3-Na2CO3(H2CO3的pKa2 = 10.33)
B. HAc - NaAc(HAc的pKa = 4.756)
C. NH4Cl – NH3·H2O(NH3·H2O的pKb = 4.75)
D. Na2HPO4 – Na3PO4(H3PO4的pKa3 = 12.32)

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人体血液的pH值总是维持在7.35〜7.45这一狭小的范围内。其中主要原因是由于( )

A. 血液中的HCO3-和H2CO3只允许维持在一定的比率范围内
B. 人体内有大量的水分(约占体重的70%)
C. 排出的CO2气体一部分溶在血液中
D. 排出的酸性物质和碱性物质溶在血液中

某缓冲溶液的共轭碱的Kb=1.0×10-6,从理论上推算该缓冲溶液的缓冲范围是( )

A. 6~8
B. 7~9
C. 5~7
D. 5~6

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