"Published in Newark, California, USA"
An EDTA solution prepared from its disodium salt was standardized using 506.3 mg of primary standard CaCO3 and consumed 28.50 mL of the solution. The standard solution was used to determine the hardness of a 2L sample of mineral water, which required 35.57 mL EDTA solution. Express the analysis in terms of ppm CaCO3.
Solution:
If CaCO3 is used to standardized EDTA disodium salt solution, then the chemical reaction is
From the chemical reaction above, we can calculate the concentration of EDTA disodium salt solution as follows
If the standardized EDTA disodium salt solution is used to determine the hardness of mineral water, then the amount of CaCO3 is
Therefore, the amount of CaCO3 in ppm is
