Sulfuric Acid
H2SO4 98.08

Sulfuric acid.
Sulfuric acid [7664-93-9].
» Sulfuric Acid contains not less than 95.0 percent and not more than 98.0 percent, by weight, of H2SO4.
Caution—When Sulfuric Acid is to be mixed with other liquids, always add it to the diluent and exercise great caution.
Packaging and storage— Preserve in tight containers.
Identification— It responds to the tests for Sulfate 191.
Residue on ignition 281 Evaporate 22 mL (40 g) to dryness, and ignite: not more than 2 mg of residue remains (0.005%).
Chloride 221 A dilution of 1.1 mL (2.0 g) in water shows no more chloride than corresponds to 0.15 mL of 0.020 N hydrochloric acid (0.005%).
Arsenic 211 Add 1.6 mL (3.0 g) to 3 mL of nitric acid and 20 mL of water, and evaporate until dense fumes of sulfur trioxide form. Cool, and cautiously wash the solution into an arsine generating flask with 50 mL of water; the resulting solution meets the requirements of the test, the addition of 20 mL of dilute sulfuric acid (1 in 5) specified for Procedure being omitted (1 ppm).
Heavy metals 231 Add 2.2 mL (4.0 g) to about 10 mg of sodium carbonate dissolved in 10 mL of water. Heat until almost dry, add 1 mL of nitric acid, evaporate to dryness, add 2 mL of 1 N acetic acid to the residue, and dilute with water to 25 mL: the limit is 5 ppm.
Reducing substances— Carefully dilute 4.4 mL (8.0 g) with about 50 mL of ice cold water, keeping the solution cold during the addition. Add 0.10 mL of 0.10 N potassium permanganate: the solution remains pink for 5 minutes.
Assay— Place about 1 mL of Sulfuric Acid in an accurately weighed, glass-stoppered flask containing about 20 mL of water, and weigh again to obtain the weight of the test specimen. Dilute with about 25 mL of water, cool, add methyl orange TS, and titrate with 1 N sodium hydroxide VS. Each mL of 1 N sodium hydroxide is equivalent to 49.04 mg of H2SO4.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Robert H. Lafaver, B.A.
(EM105) Excipient Monographs 1
USP32–NF27 Page 1365
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.