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17-28. An EDTA solution was prepared by dissolving approximately 4 g of the disodium salt in approximately 1 L of water. An average of 42.35 mL of this solution was required to titrate 50.00-mL aliquots of a standard that contained 0.7682 g of MgCO, per liter. Titration of a 25.00-mL sample of mineral water at pH 10 required 18.81 mL of the EDTA solution. A 50.00-mL aliquot of the mineral water was rendered strongly alkaline to precipitate the magnesium at Mg(OH)2. Titration with a calcium-specific indicator required 31.54 mL of the EDTA solution. Calculate a. the molar concentration of the EDTA solution. b. the concentration of CaCO3 in the mineral water in ppm. c. the concentration of MgCO, in the mineral water in ppm.