A white, heavy powder with a pearly luster, slightly hygroscopic. Soluble in hydrochloric acid, nitric acid, and dilute sulfuric acid; insoluble in water and alcohol. Commonly used in the pharmaceutical industry as a neutralizer of stomach acid and an astringent, used to treat gastric and duodenal ulcers and diarrhea.
1. While stirring, add 20 mL of a concentrated solution of bismuth subnitrate and 5% nitric acid dropwise to 500 mL of boiling water. Allow to cool and stand, filter, and wash. Dry at 30-40℃.
2. Dissolve bismuth subnitrate in distilled water to form a saturated solution, then slowly add it to a large volume of hot distilled water while stirring to hydrolyze: Bi(NO3)3 + H2O ﹦ BiONO3↓ + 2HNO3. After the reaction is complete, add ammonia water with a density of 0.91 to neutralize the nitric acid until the solution pH is below 3.0 to remove impurity ions such as Pb2+, Ag+, Cu2+, and Fe3+. Allow to stand to allow complete precipitation. Separate the supernatant, filter the precipitate, wash it 5-6 times with cold water, and dry it in the air.
