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TARTAR

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Originally appearing in Volume V26, Page 436 of the 1911 Encyclopedia Britannica.
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TARTAR , the name commonly applied to crude See also:

acid See also:potassium tartrate or " bitartrate of potash," HK(C4H406). During the See also:process of See also:fermentation wines See also:deposit a crystalline crust of See also:argol; this, after being roughly purified by recrystallization, is known as tartar, and when further purified and freed from colouring matters becomes " cream of tartar," also called technically " cream." With the iatrochemists tartar was a generic See also:term which included both this See also:tartarus vini and various substances obtained from it, and even salts, such as See also:salt of See also:sorrel (potassium oxalate), that resembled it. Thus sal fixum tartari was potassium carbonate, which on exposure to the See also:air deliquesces to oleum tartari per deliquium; neutral potassium tartrate was called tartarus tartarisatus, because it was prepared by neutralizing See also:ordinary tartar with the sal fixum; tartarus chalybeatus was a preparation with See also:iron; and spiritus tartari, used by See also:Paracelsus, was prepared by dry See also:distillation of tartar. Paracelsus also used the term in a still wider sense to signify abnormal precipitates or sediments deposited from See also:animal secretions; the same See also:idea is apparent in the popular application of the word to the salivary calculus which forms on the See also:teeth. Cream of tartar is prepared by dissolving granulated argol in boiling See also:water and allowing the See also:solution to stand. The clear liquid is then See also:drawn off and crystallized. The slightly coloured crystals thus obtained are redissolved in hot water, the colouring matters got rid of by means of pipeclay or See also:egg-albumen, and the solution filtered and crystallized, the name " crean of tartar " being originally applied to the crust of See also:minute crystals that See also:form on its See also:surface as it cools. The salt crystallizes in masses of small, hard, colourless, trans-See also:parent, rhombic prisms. It is precipitated when an excess of a potassium salt is added to a solution of tartaric acid, but it dissolves in See also:mineral acids, and in alkalis and alkaline See also:carbonates. Solutions of boric acid or See also:borax dissolve it freely, forming soluble cream of tartar, which is a See also:white See also:powder permanent in the air when made with the acid, but deliquescent when borax is employed. Its slight solubility in See also:alcohol explains why it is deposited by wines as they mature. One See also:part by See also:weight of the salt dissolves in 15 parts of boiling water, but at See also:lower temperatures the solubility is greatly diminished, and at o° C. about 416 parts of water are required.

When heated it is decomposed with formation of potassium carbonate and See also:

carbon, inflammable gases having an odour of burnt See also:bread being evolved. The salt is used for the manufacture of tartaric acid ; it is also employed in the See also:mordant See also:bath for See also:wool-See also:dyeing, with powdered See also:chalk and See also:alum for cleaning See also:silver, and for the preparation of effervescing drinks and See also:baking-powder. In See also:medicine as potassii tariras acidus it is of some slight importance as a diuretic and purgative. The more soluble normal salt, K2(C4H406), is used for the same purposes; it is formed by dissolving powdered cream of tartar in a hot solution of potassium carbonate. If See also:sodium carbonate is substituted the result is KNa(C4H406), or Rochelle salt. Tartar emetic (potassium antimonyl tartrate) K. (SbO) C4H406•1H2O. This substance has been known for a See also:long See also:period, being mentioned by See also:Basil See also:Valentine. It may be prepared by warming 3 parts of antimonious See also:oxide with 4 parts of cream of tartar, in the presence of water, replacing the water as it evaporates; after digestion is See also:complete, the solution is filtered hot. Powder of See also:algaroth (q.v.) may be used in See also:place of the See also:antimony oxide. Tartar emetic crystallizes in small octahedra, which lose their water of See also:crystallization gradually on exposure to air, and become opaque. It is soluble in 14.5 parts of See also:cold water and 1.9 parts of hot, the solution showing an acid reaction to See also:litmus.

It possesses a nauseous metallic See also:

taste and produces vomiting when taken internally, whilst in large doses it is poisonous. It is used medicinally, and also as a mordant in dyeing and See also:calico-See also:printing.

End of Article: TARTAR

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TARTARIC ACID (dihydroxy-succinic acid), C4H6O6

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