3. A water source contains 100.0 mg/L of CO3^2- and 75.0 mg/L of HCO3 at pH 10. Calculate the alkalinity exactly at 25°C in units of mg/L as CaCO3. Next,

approximate the alkalinity by ignoring[OH-] and [H+]. Comment on when it is or is not appropriate to use the approximate solution and why.

Fig: 1