Complex Determination of Water Hardness
Complexometric Determination of Water Hardness.
Abstract:
Using complexometric method of calculating water hardness, an EDTA solution was made and calculated to be around .00209M. This EDTA solution was then used to titrate a water sample with unknown hardness. The sample used was sample #18. The hardness of the sample was calculated to be 180505 ppm. This is within normal levels for the Mesa area.
Introduction: This experiment focuses on titration with EDTA. Titration is the determination of a given component in solution by addition of a liquid reagent of known strength until the endpoint is reached when the component has been consumed by reaction with the reagent. An indicator called Eriochrome Black T will enable detection when the EDTA has completely chelated the metal impurities. Chelation happens when a ligand (with more than one binding site) forms a complex with a metal ion. Ligands are complexes that form when the electron donating groups form coordinate covalent bonds through empty orbitals on the metal ion.
This experiment contains Ammonium chloride buffer which is an inhalation irritant.
Procedure: About 500 mL of approximately 0.004 M disodium EDTA solution needed. The solution should have between 0.7–0.8 g of Na2EDTA and dissolve in about 500 mL deionized water in a plastic bottle. The bottled is Sealed and shaken vigorously for a few minutes to dissolve the salt. Standardize the Na2EDTA solution using a stock calcium ion solution as the primary standard. Using a 10-mL transfer pipet to add 10.00 mL of standardized calcium ion stock solution (1.000 g CaCO3/L solution) to a 250-mL Erlenmeyer flask which will have an additional 30 ml of deionized water to this titration flask. Adding a magnetic stir-bar the solution was then stirred. about 3 mL of ammonia/ammonium chloride buffer is added to the solution. Just prior to titrating the flask, adding four drops of Eriochrome Black T indicator
Abstract:
Using complexometric method of calculating water hardness, an EDTA solution was made and calculated to be around .00209M. This EDTA solution was then used to titrate a water sample with unknown hardness. The sample used was sample #18. The hardness of the sample was calculated to be 180505 ppm. This is within normal levels for the Mesa area.
Introduction: This experiment focuses on titration with EDTA. Titration is the determination of a given component in solution by addition of a liquid reagent of known strength until the endpoint is reached when the component has been consumed by reaction with the reagent. An indicator called Eriochrome Black T will enable detection when the EDTA has completely chelated the metal impurities. Chelation happens when a ligand (with more than one binding site) forms a complex with a metal ion. Ligands are complexes that form when the electron donating groups form coordinate covalent bonds through empty orbitals on the metal ion.
This experiment contains Ammonium chloride buffer which is an inhalation irritant.
Procedure: About 500 mL of approximately 0.004 M disodium EDTA solution needed. The solution should have between 0.7–0.8 g of Na2EDTA and dissolve in about 500 mL deionized water in a plastic bottle. The bottled is Sealed and shaken vigorously for a few minutes to dissolve the salt. Standardize the Na2EDTA solution using a stock calcium ion solution as the primary standard. Using a 10-mL transfer pipet to add 10.00 mL of standardized calcium ion stock solution (1.000 g CaCO3/L solution) to a 250-mL Erlenmeyer flask which will have an additional 30 ml of deionized water to this titration flask. Adding a magnetic stir-bar the solution was then stirred. about 3 mL of ammonia/ammonium chloride buffer is added to the solution. Just prior to titrating the flask, adding four drops of Eriochrome Black T indicator