Diluted Hydrochloric Acid
» Diluted Hydrochloric Acid contains, in each 100 mL, not less than 9.5 g and not more than 10.5 g of HCl.
Diluted Hydrochloric Acid may be prepared as follows:
Hydrochloric Acid 226 mL
Purified Water, a sufficient quantity, to make 1000 mL
Mix the ingredients.
Packaging and storage— Preserve in tight containers.
Identification— It responds to the tests for Chloride 191.
Residue on ignition 281 To 20 mL add 2 drops of sulfuric acid, evaporate to dryness, and ignite: the weight of the residue does not exceed 2 mg.
Sulfate— To a mixture of 3 mL of it and 5 mL of water add 5 drops of barium chloride TS: neither turbidity nor precipitate appears within 1 hour.
Sulfite— On the completion of the test for Sulfate, the further addition to the liquid of 2 drops of 0.1 N iodine produces neither turbidity nor decolorization of the iodine.
Heavy metals 231 To 3.8 mL (4 g) add 5 mL of water and 1 drop of phenolphthalein TS. Add 6 N ammonium hydroxide until the solution assumes a faint pink color. Add 2 mL of 1 N acetic acid, then add water to make 25 mL: the limit is 5 ppm.
Free bromine or chlorine— To 10 mL add 1 mL of potassium iodide TS and 1 mL of chloroform, and agitate the mixture: the chloroform remains free from any violet coloration for at least 1 minute.
Assay— Transfer 10.0 mL of Diluted Hydrochloric Acid to a conical flask, and add about 20 mL of water. Add 3 drops of methyl red TS, and titrate with 1 N sodium hydroxide VS. Each mL of 1 N sodium hydroxide is equivalent to 36.46 mg of HCl.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, M.S.
Scientific Liaison
(EXC2010) Monographs - Excipients
USP35–NF30 Page 1818