(1)写出电池符号和电池反应方程式；
Ag(s)/AgCl(s),Cl-(1.0 M)//HA (0.5 M),A-(0.10 M)/ 氢电极
2HA + 2Ag + 2Cl- ---> 2AgCl + H2 + 2A-
(2)计算正、负极的电极电势；
负极的电极电势:
E(AgCl/Ag)=E(Ag+/Ag）+ 0.05916log[Ag+]=
E(Ag+/Ag）+ 0.05916log(Ksp/[Cl-])=
=0.7996 + 0.05916logKsp -0.05916log[Cl-]
=0.7996 + 0.05916logKsp
E(cell)=0.450=E(正)-E(AgCl/Ag)
正极的电极电势:
E(正)=0.450+E(AgCl/Ag)
(3)计算负极(?)溶液中的c(H+)和HA解离常数.
E(正)=0.450+E(AgCl/Ag)=(0.05916/2)log([H+]^2/P(H2))
=0.02958log(Ka^2[HA]^2/[A-]^2P(H2)
=0.02958log(Ka^2x0.25)
so,Ka= .