The character of the acidity, however, changes, the free tartaric acid gradually disappearing, forming bitartrate of potash and being otherwise broken up. On the other hand, the free malic acid increases and the tannin decreases.
In alkaline solution, potassium permanganate oxidizes it to inactive tartaric acid and carbon dioxide (0.
In repeating and extending the experiments of Haiiy much later, Sir David Brewster discovered that various artificial salts were pyro-electric, and he mentions the tartrates of potash and soda and tartaric acid as exhibiting this property in a very strong degree.
The preparations of lithium used in medicine are: Lithii Carbonis, dose 2 to 5 grs.; Lithii Citras, dose 5 to io grs.; and Lithii Citras effervescens, a mixture of citric acid, lithium citrate, tartaric acid and sodium bicarbonate, dose 60 to 120 grs.
Citric acid is also distinguished from tartaric acid by the fact that an ammonia solution of silver tartrate produces a brilliant silver mirror when boiled, whereas silver citrate is reduced only after prolonged ebullition.
Absence of rotary power when asymmetric carbon atoms are present, may be caused by an internal compensation within the molecule as with the inactive tartaric acid (mesotartaric acid), or may be due to the fact that the compound is an equimolecular mixture of leftand right-hand varieties, this being the case with racemic acid that was broken by Louis Pasteur into laevoand dextro-tartaric acid (see Stereo-Isomerism).
If taken in overdose or in a concentrated form tartaric acid produces severe gastro-enteritis.
At the beginning of July when the berries have attained to an appreciable size - the specific gravity of the juice is very low; it contains very little sugar, but a good deal of acid, chiefly free tartaric acid and malic acid.
Kekule (Ann., 1883, 221, p. 230), however, reinvestigated this acid; he showed that it was dibasic and not tribasic; that it gave tartaric acid on reduction; and, finally, that it was dioxytartaric acid, HOOC C(OH) 2 C(OH) 2 COOH.