|
|
;)
292.24[60-00-4].
197K
.
281:
not more than 0.2%.
231:
0.003%.
until most of the carbon is consumed. Cool, add 0.15 mL of nitric acid, and heat at 500 until all of the carbon is consumed. Dissolve the residue in 2 mL of a mixture of equal volumes of hydrochloric acid and water, digest in a covered dish on a steam bath for 10 minutes, remove the cover, and evaporate to dryness. Dissolve the residue in 1 mL of 1 N acetic acid and 20 mL of hot water, digest for 5 minutes on a steam bath, cool, and dilute with water to 30 mL. To 2.0 mL of this solution add 2 mL of hydrochloric acid, and dilute with water to 50 mL. Add about 50 mg of ammonium persulfate and 3 mL of ammonium thiocyanate solution (3 in 10), mix, and transfer to a color-comparison tube. Treat in the same manner 2.0 mL of a solution of ferric ammonium sulfate, prepared by dissolving 43.2 mg of ferric ammonium sulfate in 10 mL of 2 N sulfuric acid and adding water to make 1000 mL, each mL representing 5 µg of Fe. The color of the test solution is not deeper than that of the solution containing the standard iron solution (0.005%).
467:
meets the requirements.
for 2 hours, cooled in a desiccator, and accurately weighed. Add 10 mL of water, swirl to form a slurry, and cover the beaker with a watch glass. Without removing the watch glass, add 2 mL of 3 N hydrochloric acid from a pipet, and swirl to dissolve. Wash down the sides of the beaker, the outer surface of the pipet, and the watch glass with water, and dilute with water to about 100 mL. While stirring with a magnetic stirrer, add about 30 mL of the Assay preparation from a 50-mL buret. Add 10 mL of 1 N sodium hydroxide and 300 mg of hydroxy naphthol blue, and continue the titration with the Assay preparation to a blue endpoint. Calculate the weight, in g, of C10H16N2O8 in the portion of Edetic Acid taken by the formula: