1. [25 pt] The stability of a water can be estimated using the so-called Langelier Saturation Index (LSI). Suppose the drinking water from DWTP has the following analysis: CO32- = 16 mg/L Na+ = 20 mg/L Mg2+ = 15 mg/L = HCO3 = 189 mg/L Ca2+ = 63 mg/L Cl* = 10 mg/L /L K+ = 10 mg/L SO42- = 80 mg/L Temperature = 25 C = a) Calculate the pH of the water. (Note that Ka2 (HCO3-7C032-) is 10-10.33 at 25 C) b) Calculate the Alk and Ca-Hardness of the water in mg/L as CaCO3, respectively. c) Calculate the TDS of the water in mg/L d) Calculate the saturation pH (PH3) of the water. e) Calculate Langelier Saturation Index (LSI) for the water and determine whether the water is oversaturated or undersaturated with respect to CaCO3 and the water is corrosive or not