27 ppm 13819 ppm Table 2 Viva Mineralized Water Analysis Titration Data Trial 1

27 ppm 13819 ppm table 2 viva mineralized water

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95% and the resulting interval is [112.27 ppm, 138.19 ppm]. Table 2. Viva! Mineralized Water Analysis Titration Data Trial 1 2 3 Water 50 mL 50 mL 50 mL 2 4 2 10 Ca + EDTA CaEDTA 5.0 10 f K x 2 4 2 8 Mg + EDTA MgEDTA 4.9 10 f K x 2+ 2- Mg + HIn MgIn +H - 4- + 2- 2- 3 2 MgIn +Y +H O MgY +HIn +H O ( - ) ( ) red wine clear blue
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sample Final vol of EDTA 8.9 mL 18.4 mL 27.2 mL Initial vol of EDTA 0 mL 8.9 mL 18.4 mL Net vol EDTA 8.9 mL 9.5 mL 8.8 mL Total Hardness 122.93 ppm 131.21 ppm 121.55 ppm The total cation content of the water sample based from label’s given Ca 2+ and Mg 2+ content was also computed by adding the total CaCO 3 ppm and total CaCO 3 ppm from MgCO 3 is 192.57 ppm, which can be classified as very hard water. Comparing this with respect to the data obtained from EDTA titration, it claims to have a higher Ca 2+ and Mg 2+ content when the computed total hardness from complexometric titration appears to be less. The large difference of the total hardness of the two may due to different errors arose during the titration or preparation of the solution. The discrepancy may be caused by several factors. Overtitration of the sample analysis is the common source of error since the detection of blue endpoint is not distinguishable to purple color. The delayed change of color of the solution can also be the cause of overtitration. It is also important to note that the indicator used must be suitable for the type of titration, which in this experiment we used EBT since it selectively binds with the Mg 2+ ions. Neglect to add buffer can also cause error in the concentration of the standardized EDTA since it is very sensitive to pH change, so it is also important to note that proper selection of kind of buffer based on each pH range, in which in this experiment, is at 10. Another titration was done to determine the hardness of tap water. Table 3 below shows the titration data of the tap water titrated with standardized EDTA and the computed average total hardness as CaCO 3 ppm is 62.15 ppm which is classified as moderately hard based from table 1. Table 3. Tap Water Analysis Titration Data Trial 1 2 Water sample 50 mL 50 mL Final vol of EDTA 4.5 mL 9.0 mL Initial vol of EDTA 0 mL 4.5 mL Net vol EDTA 4.5 mL 4.5 mL Total Hardness 62. 15 ppm 62.15 ppm Compared to the commercial mineral water’s total hardness, it is as half as much of it. But daily consumption of this kind of water is not advisable because it may contain chloride (to kill germs) that can easily react with other organic materials, and other alkaline substance (to maintain pH and prevents corrosion of pipes). SUMMARY AND CONCLUSIONS The standardized EDTA resulted to a 0.0069 M after titrating it thrice with primary standard CaCO 3 . Viva! Mineralized water was used as sample and has an initial Ca 2+ content of 54 ppm and Mg 2+ content with 14 ppm. The water sample was titrated with standardized EDTA using EBT indicator. The selection of the indicator was based on the range of its pH which is 8 to 10. NH 3 -NH 4 Cl buffer with pH at 10 was used to maintain the pH of the solution since EDTA is pH dependent. After three trials of titration, the
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  • Fall '17
  • Sir Jaden Smith
  • Drinking water, Hard water, Calcium carbonate

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