TARTARIC ACID

is dihydroxysuccinic acid, (CHOHCOOH)., which fon account of its containing two asymmetric carbon atoms, exists in four ordinary tartaric acid, levo-tartaric acid, mesoor inactive tartaric acid, and racemic acid, the latter being a mixture of the two first-named varieties. Ordinary tartaric acid occurs in many plants, particularly the grape; from the tartar or argol, which is the deposit obtained on the fermentation of wine, it is principally obtained. It forms large clear crystals, and behaves as a dibasic acid, the principal salts of which are the acid pota ium tartrate, or cream of tartar; pota ium sodium tartrate, or Rochelle salt; and tartar emetic. Its solution rotates polarized light to the right. Ordinary tartaric acid is used in the preparation of effervescing mixtures and baking powder, and in dyeing-