31. 下列哪個酸性化合物可用來準備 pH = 8.60 的緩衝溶液？
(A) HA (Ka = 2.7 ✖ 10−3)
(B) HB (Ka = 4.4✖ 10−6)
(C) HC (Ka = 2.6✖ 10−9)
(D) HD (Ka = 4.6✖10−12)

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統計： A(8), B(15), C(181), D(7), E(0) #3276993

詳解 (共 2 筆)

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[配置緩衝溶液的選擇—相同觀念考古題]
33. 為配置適用於 pH＞4.0 且最接近 pH 4.0 之緩衝液(buffer)，哪一個弱酸(weak acid)水溶液可與等當量(equivalent)的強鹼(strong base)進行配置最為適當？
(A) Hydrofluoric acid, HF；66b9c47334b4f.jpg#s-99,20
(B) Lactic acid , HLAc； 66b9c4792ede8.jpg#s-101,23
(C) Acetic acid, HC2H3O4；66b9c481aa824.jpg#s-100,24
(D) Benzoic acid, HC7H5O2； 66b9c4888e1e6.jpg#s-97,26
答案：D
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義守：99義守(30)
31. 假設等濃度的共軛酸鹼對，下列那一組適宜製備 pH 9.2–9.3 的緩衝溶液？
(A) CH3COONa/CH3COOH (Ka = 1.8 x 10–5)
(B) NH3/NH4Cl (Ka = 5.6 x 10–10)
(C) NaOCl/HOCl (Ka = 3.2 x 10–8)
(D) NaNO2/HNO2 (Ka = 4.5 x 10–4)
答案：B
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21. 欲製備 pH 5.0 的緩衝溶液，使用下列那一種酸及其鈉鹽最合適？
(A) monochloroacetic acid (Ka = 1.35 × 10−3 )
(B) nitrous acid (Ka = 4.0 × 10−4 )
(C) propanoic acid (Ka = 1.3 × 10−5 )
(D) benzoic acid (Ka = 6.4 × 10−5 )
答案：C
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33. 化學家需要使用有機酸與其鈉鹽製備 pH = 4.90 的緩衝溶液，下列哪種有機酸的效果最好？
(A) 丙酸（Ka = 1.3 × 10–5）
(B) 氯乙酸（Ka = 1.35 × 10–3）
(C) 乙酸（Ka = 1.8 × 10–5）
(D) 苯甲酸（Ka = 6.4 × 10–5
答案：A
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高醫：106高醫(90)
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
答案：B
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