14. 已知CH3COOH之ka = 1.8 ✕ 10–5 ,請問當水中有一緩衝系統內含1.0 M CH3COOH及1.0 M CH3COONa時之pH為多少?
(A) 4.65
(B) 4.89
(C) 2.49
(D) 4.74
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統計: A(2), B(8), C(6), D(105), E(0) #1537261
統計: A(2), B(8), C(6), D(105), E(0) #1537261
詳解 (共 1 筆)
#4335421
HA --> A- + H+
0.1-x 0.1+x x , 1000ka < 0.1 , x 極小可略
ka = (0.1*x)/0.1 =1.8*10-5
[H+] = x = 1.8*10-5
pH= -log(1.8*10-5 ) = 4.74
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