What is the pH of 0.050 M diethylamine?

What is the pH of 0.050 M diethylamine?

(diethylamine의 Kb = 1.3×10^-3)

 

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................(C2H5)2NH(aq) + H2O((l) ⇌ (C2H5)2NH2^+(aq) + OH^-(aq)

평형에서, ... 0.050-x .......................... x .......................... x

 

 

Kb = [(C2H5)2NH2^+][OH^-] / [(C2H5)2NH]

= x^2 / (0.050-x) = 1.3×10^(-3)

 

x^2 + 1.3×10^(-3)x – ((1.3×10^(-3)) × 0.050) = 0

 

근의 공식으로 x를 계산하면,

x = 0.00743842 = [OH^-]

 

pOH = -log(0.00743842) = 2.13

pH = 14.00 – 2.13 = 11.87

 

 

답: 11.87

 

 

[키워드] 디에틸아민의 pH