TARTARIC ACID 267 



AoiDUM Taetaeicum. Tartaric Acid. H,C,H,Oe. 

 (U.S.&B.P.) 



- Synonym. — Sal essentials tartari, — acide tartrique, 

 acide de tartre, Fr.; weinsaure, weinsteinsaure, G. 



Derivation. — Boil acid potassium tartrate or argol 

 (incrustation in wine casks) with chalk to form calcium 

 tartrate. 2 K H C,H,0, + Ca C 0, = Ca C,H,Oe + K,C,H,0, 

 + HjO + C Oj. Add calcium chloride, which precipitates 

 more calcium tartrate, and decompose with sulphuric acid. 

 H,S O, + Ca C,H,Oe = H,C,H,0, + Ca S O, 



Evaporate solution. Calcium sulphate crystals separate 

 and are removed, while tartaric acid crystallizes on further 

 evaporation. 



Properties. — Colorless, translucent, monoclinic prisms, 

 or crystalline crusts, or a white powder ; odorless, having a 

 purely acid taste, and permanent in the air. Soluble in 

 about .8 part of water, and in 2.5 parts of alcohol. Not 

 commonly used in Veterinary medicine. 



Dose.—K., 3 ii.-iv. (8.-15.); D., gr.x.-sxx. (.6-2.). 



AciDUM CiTEicuM. Citric Acid. H3CeH,0,. (U. S. & B. P.) 



Synonym. — Acidum citri S. limonum, S- limonorum, — 

 acide citrique, acide du citron, Fr.; citron ensaure, G. 



Derivation. — Usually prepared from the lemon (Citrus 

 lempnum), or lime (Citrus bergamia). Boiling lemon juice 

 (containing 7 per cent, of citric acid) is treated with chalk 

 to form calcium citrate. 2 HjCjIIjO, + 3 Ca C O3 = Ga.^ 

 (aH,0,), 4- 3 C O, + 3 H,0. 



Calcium citrate is boiled with sulphuric acid and the 

 resulting citric acid is obtained by filtration, evaporation 

 and crystallization. Caj (CeHjO,)^ -|- 3 Hj S O^ = 2 HjCbHs 

 O, -h 3 Ca S O,. 



Properties. — Colorless, translucent, right - rhombic 

 prisms; odorless, having an agreeable, purely acid taste; 

 efflorescent in warm air and deliquescent when exposed to 



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