Sodium Hydroxide
NaOH 40.00

Sodium hydroxide.
Sodium hydroxide [1310-73-2].
» Sodium Hydroxide contains not less than 95.0 percent and not more than 100.5 percent of total alkali, calculated as NaOH, including not more than 3.0 percent of Na2CO3.
Caution—Exercise great care in handling Sodium Hydroxide, as it rapidly destroys tissues.
Packaging and storage— Preserve in tight containers.
Identification— A solution (1 in 25) responds to the tests for Sodium 191.
Insoluble substances and organic matter— A solution (1 in 20) is complete, clear, and colorless to slightly colored.
Potassium— Acidify 5 mL of a solution (1 in 20) with 6 N acetic acid, then add 5 drops of sodium cobaltinitrite TS: no precipitate is formed.
Heavy metals 231 Dissolve 0.67 g in a mixture of 5 mL of water and 7 mL of 3 N hydrochloric acid. Heat to boiling, cool, and dilute with water to 25 mL: the limit is 0.003%.
Assay— Dissolve about 1.5 g of Sodium Hydroxide, accurately weighed, in about 40 mL of carbon dioxide-free water. Cool the solution to room temperature, add phenolphthalein TS, and titrate with 1 N sulfuric acid VS. At the discharge of the pink color of the indicator, record the volume of acid solution required, add methyl orange TS, and continue the titration until a persistent pink color is produced. Each mL of 1 N sulfuric acid is equivalent to 40.00 mg of total alkali, calculated as NaOH, and each mL of acid consumed in the titration with methyl orange is equivalent to 106.0 mg of Na2CO3.
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 1343
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.