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 (K_a = 1.8 x 10^–5)
(B) NH₃/NH₄Cl (K_a = 5.6 x 10^–10)
(C) NaOCl/HOCl (K_a = 3.2 x 10^–8)
(D) NaNO₂/HNO₂ (K_a = 4.5 x 10^–4)

阿摩線上測驗 · 2017-06-09T14:13:41+08:00

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)

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統計： A(12), B(482), C(13), D(7), E(0) #1599853

詳解 (共 3 筆)

瑤軒(已上榜

B2 · 2022/07/28

#5572929

找pKa跟「要製備的溶液的pH值」最近的(pKa = -logKa)
(A) pKa = 5 - log1.8 = 4.~
(B) pKa = 10 - log5.6 = 9.~(跟要配的pH值最近)
(C) pKa = 8 - log3.2 = 7.~
(D) pKa = 4 - log4.5 = 3.~