碳酸是CO2的水溶液,其饱和H2CO3溶液的浓度约为0.040mol/L,
c(H+)=cKa1开平方=1.3X10^-4mol/L PH=3.9
碳酸氢根,c(H+)=Ka1XKa2开平方=4.8X10^-9mol/L PH=8.3