Alkalinity has been defined as the acid-neutralizing capacity of a water, and we commonly use the following definition for the alkalinity of natural waters: Alk (eq/L) = [OH] + [HCO3] + 2[CO32]-[H]; where [X] = molar concentration of species X (a) Why is there a 2 in front of the carbonate concentration? (b) In the lab you saw that acetic acid (CH3COOH or HAC) with pK, = 4.76 exhibited pH buffering in the pH range 4.5 to 5; this suggests that acetic acid should contribute to Alkalinity. How is it that the acetic acid species are not listed in the definition of Alk? (c) Given a natural water with pH = 8, Alk= 50 mg/L as CaCO3, and pK = 6.35 and pK = 10.33 for carbonic acid, report the molar concentrations of each of the carbonic acid species: [HCO3], [HCO3] and [CO3].