ARSENIC ACID

H 3 AsO 4 . Syn. Acidum arsen′icum , L.; Acide arsénique , Fr.; Arsenicsäure , Ger. Prep. 1. Arsenious acid, in fine powder, 2 parts; concentrated nitric acid, 6 parts; hydrochloric acid, 1 part; mix in a flask or tubulated retort, and digest, with heat, until solution is complete; after repose, decant the clear portion and evaporate, to the consistence of a thick syrup. 2. Di olve arsenious acid in hot hydrochloric acid, and when the solution is cold add concentrated nitric acid, in small quantities at a time, until red vapours cease to be evolved, then proceed as before. Prop. Thick syrup, occasionally forming clear transparent crystals, very deliquescent, readily soluble in water, and converted by heat into the anhydrous acid. Extremely poisonous.