A.) The flask shown here contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.230 M NaOH.
What volume of NaOH is needed to reach the end point of the titration? Answer 31mL
What was the initial concentration of HCl? Hardness in groundwater is due to the presence of metal ions, primarily Mg2 and Ca2 .
B.) Hardness is generally reported as ppm CaCO3. To measure water hardness, a sample of groundwater is titrated with EDTA, a chelating agent, in the presence of the indicator eriochrome black T, symbolized here as In. Eriochrome black T, a weaker chelating agent than EDTA, is red in the presence of Ca2 and turns blue when Ca2 is removed.
A 50.00-mL sample of groundwater is titrated with 0.0350 M EDTA. Assume that Ca2 accounts for all of the hardness in the groundwater. If 14.10 mL of EDTA is required to titrate the 50.00-mL sample, what is the hardness of the groundwater in molarity and in parts per million of CaCO3 by mass?
A.) The flask shown here contains 10.0 mL of HCl and a few drops of phenolphthalein indicator. The buret contains 0.230 M NaOH.
What volume of NaOH is needed to reach the end point of the titration? Answer 31mL
What was the initial concentration of HCl? Hardness in groundwater is due to the presence of metal ions, primarily Mg2 and Ca2 .
B.) Hardness is generally reported as ppm CaCO3. To measure water hardness, a sample of groundwater is titrated with EDTA, a chelating agent, in the presence of the indicator eriochrome black T, symbolized here as In. Eriochrome black T, a weaker chelating agent than EDTA, is red in the presence of Ca2 and turns blue when Ca2 is removed.
A 50.00-mL sample of groundwater is titrated with 0.0350 M EDTA. Assume that Ca2 accounts for all of the hardness in the groundwater. If 14.10 mL of EDTA is required to titrate the 50.00-mL sample, what is the hardness of the groundwater in molarity and in parts per million of CaCO3 by mass?
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