試題詳解

63. A chemist needs to prepare a buffered solution using one of the following acids (and its sodium salt): HA (Ka = 1.4 × 10^-3 ), HB (Ka = 9.8 × 10^-6 ), HC (Ka = 8.4 × 10^-5 ), HD (Ka = 3.5 × 10^-7 ), HE (Ka = 1.9 × 10^-8 ). To prepare a solution buffered at pH = 5.10, which system will work best (a buffer with the best capacity)?
(A) HA and its sodium salt
(B) HB and its sodium salt
(C) HC and its sodium salt
(D) HD and its sodium salt
(E) HE and its sodium salt