Example 13.4b: Calculation of pH from [H3O+]

Water exposed to air contains carbonic acid, \(\ce{H2CO3}\), due to the reaction between carbon dioxide and water:

\(\ce{CO2(aq)}\)\(\ce{ + }\)\(\ce{H2O(l)}\)\(\ce{<=>}\)\(\ce{H2CO3(aq)}\)\(\ce{ }\)

Air-saturated water has a hydronium ion concentration caused by the dissolved \(\ce{CO2}\) of \(2.0\times 10^{-6 }\)M, about 20-times larger than that of pure water. Calculate the pH of the solution at 25 °C.

Think about it...