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【简答题】
Nearly two-thirds agreed that "cash and credit cards will have mostly disappeared" and been replaced with "smart" devices able to carry out a transaction. But a third of the survey respondents countered that consumers would fear for the security of transactions over a mobile device and worry about surrendering so much data about their purchasing habits.
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【单选题】3-下列溶液用酸碱滴定法能准确滴定的是 -( ) (A) 0.1 mol/LHF (pKa = 3.18) (B) 0.1 mol/L HCN (pKa = 9.21) (C) 0.1 mol/LNaAc [pKa(HAc) = 4.74] (D) 0.1 mol/L NH 4 Cl [pKb(NH 3 )= 4.75]
A.
0.1 mol/LHF (pKa = 3.18)
B.
0.1 mol/L HCN (pKa = 9.21)
C.
0.1 mol/LNaAc [pKa(HAc) = 4.74]
D.
0.1 mol/L NH4Cl [pKb(NH3)= 4.75]