Pharmacopedia, a commentary on the British pharmacopoeia, 1898 / by Edmund White ... and John Humphrey.

  • White, Edmund.
Date:
1901
Catalogue details

Licence: In copyright

Credit: Pharmacopedia, a commentary on the British pharmacopoeia, 1898 / by Edmund White ... and John Humphrey. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

    49/724 (page 25)
    Acidum Nitricum. Nitric Acid is officially described as a liquid containing nearly 70 per cent, bv weight of real nitric acid, HNO„, and 30 per cent, of water, obtained by dis- tillin- sodium or potassium nitrate with sulphuric acid. A stronger acid than this is met with, known as fuming nitric acid, which contains 85-90 per cent, of HNO„. This is unstable, and partly decomposes, yielding some nitric peroxide and nitrous acid, which communicate to it a yellowish red colour. _ _ Characters and Tests.—Nitric acid is a clear colourless liquid, emitting corrosive fumes. It yields, when neutralised, the reactions characteristic of nitrates. When submitted to distillation, under normal atmospheric pressure, an acid of the official strength boils constantly at 121° C, the proportions of HNO3 and water passing over remaining unchanged throughout the dis- tillation. If an acid weaker than 70 per cent, be distilled, a larger proportion of water than nitric acid first passes over, until the residue in the still contains 70 per cent, of HNO3. With an acid stronger than 70 per cent, the reverse happens, a larger proportion of HNO3 first coming over until the residue is reduced to 70 per cent, strength. The official Acidum Nitricum has a specific gravity of 1-42. Each gramme diluted with water requires for neutralisation 11-I C.c. of N/i NaOH solution, thus— HNO3 + NaOH = NaNOg + HjO 62-58 39-76 Therefore i C.c. N/i NaOH solution = 0-06258 gramme HNO3 and ii-i ,, >, = 0-695 ,, equivalent to 69-5 per cent. Nitric acid should be free from lead, copper, arsenium, iron, chlorides, bromates, iodates, and sulphates, and it should yield no appreciable residue on evaporation. Notes.—Nitric acid manufactured from crude sodium nitrate (Chili saltpetre) sometimes contains bromic and iodic acids derived from bromides and iodides occurring in the native salt. HBr and HI are formed from those compounds by the action of the sulphuric acid, the nitric acid afterwards oxidising them to HBrOg and HIOs- Before applying the tests for bromates and iodates the nitric acid must be diluted and exactly neutralised with ammonia or soda. Acidum Nitricum Dilutum. Diluted Nitric Acid is obtained by diluting stronger nitric acid with water so that the diluted product shall contain i744 per cent, of HNO3. Tests.—Diluted nitric acid should be of specific gravity i-ioi. Each gramme neutraHses 27 C.c. of normal sodium hydroxide solution. Acidum Nitro-Hydrochloricum Dilutum. Diluted Nitro-Hydrochloric Acid is an aqueous solution containing free chlorine, hydrochloric, nitric and nitrous acids and other bodies, prepared