How to Prepare a Standard EDTA Solution

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Watch more Science Basics videos: http://www.howcast.com/videos/359846-... • When converted to a standard solution, EDTA is a useful chemical compound for titration applications such as determining the metallic content of various solutions. • Step 1: Dry and cool • Measure 4 grams of purified dihydrate ethylenediaminetetraacetic acid on the balance and dry at 80 degrees Celsius for one hour before letting it cool to room temperature in the desiccator. • Tip • The salt will contain about 0.3 percent moisture after drying and cooling. Make a note to correct the salt's weight in your calculation of the molarity of the finished solution. • Step 2: Measure • Weigh 3.8 grams and transfer it into a volumetric flask using a powder funnel. • Step 3: Add water • Rinse the funnel by pouring a small amount of distilled or deionized water through it before removing the salt. Then add enough extra purified water to make 700 milliliters. Use a dry, uncontaminated container with a non-glass stopper. • Step 4: Mix • Swirl the solution until all of the powder has dissolved. • Tip • Be patient -- it may take up to 15 minutes for the solution to be completely dissolved. • Step 5: Add water and mix • Add more purified water until it reaches the 1-liter mark, and mix well. • Step 6: Calculate molarity • Calculate the molarity, or molar concentration, of the solution. The result should be at or very close to 0.01 M. • Step 7: Finish • Store the solution with a stopper. If you plan to use it for titration, it's good practice to conduct the experiment while the solution is still fresh. • Did You Know? • EDTA was first used as a medical treatment for heavy metal poisoning in the 1940s, and is still FDA-approved for that purpose.

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