Question

在电极电势类型题中如何判断离子浓度大小

Answer 1

1) Cu2+ + 2e- = Cu

deltaG'=-2Fx0.34

2) Cu+ + e- = Cu

deltaG" =-Fx0.52

1)-2）得3)：Cu2+ + e- = Cu+

deltaG = -FE

又,deltaG = deltaG'-deltaG"= -0.68F + 0.52F = -0.16F

所以,E=0.16V

3)式两边加 Br-得：

Cu2+ + Br- + e- = CuBr E"'=0.64V

E"'=E - 0.059logKsp

所以,logKsp= (E-E"')/0.059 = （0.16-0.64)/0.059= -8.14

Ksp=10^-8.14