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Charne RutherfordDr.WeiGroup 2Quantitative analysis 3401 Determination of Water Hardness by EDTA TitrationObjective:The purpose of this Lab is to demonstrate how effective the EDTA titration techniques are by determining the hardness of stock solution sample CaCO3.Materials:1.Burette, Volumetric Flask, Erlenmeyer flask, pipet2.4mM Mg2+solution3.0.01M EDTA titrant solution4.NH3/NH4+, pH 10 buffer5.Calmagite indicator6.2400ppm CaCO3stock solutionProcedures:1.Prepare working standard solution 600ppm CaCO3 by pipeting 25mL of the 2400ppm solution into a 100mL volumetric flask. Dilute to mark and mix well.2.Make a Blank Correction:
Add approximately 25mL of distilled water into an erlenmeyer flask. Pipet exactly 2mL of the 4mM Mg2+solution, add approximately 2mL of the NH3/NH4+buffer, and 12 drops of the indicator solution. Titrate, repeat the titration on a second blank sample and average the results. Try to be as consistent as possible with the color at the endpoint. The two volumes should agree within ±0.20mL.