2*10-7mol/L HCL的PH值是多少?

2*10-7mol/L HCL的PH值是多少?
2*10-7mol/L HCL的PH值是多少?

2*10-7mol/L HCL的PH值是多少?
解PH=-lg(2*10-7mol/L)=-(lg2+lg10-7)=-(0.3-7)=6.7

pH=-lg[H+]=6.7

HCl浓度太低，要考虑水的电离
[H][OH]=10^-14
[H]=[OH]+2*10^-7
=> [H]([H]-2*10^-7)=10^-14
[H]^2-2*10^-7[H]-10^-14=0
[H]=2.414x10^-7
pH=6.62