176 MALIC ACID. 



with barium hydroxide for some time, it is broken up 

 into oxalic acid, a crystalline substance, difficultly solu- 

 ble in water, uvitic add C 9 H 8 4 (see Aromatic Com- 

 pounds), and a syrupy liquid uvitonic acid C 9 H 12 7 . 



Carbacetoxjrlic acid, C 3 H 4 O = CH 2 (OH).CO.CO. 

 OH (isomeric with malonic acid). Is produced, when 

 an aqueous solution of /3-chlorpropionic acid is boiled 

 for a long time with a great excess of silver oxide. 

 Thick syrup, easily soluble in water. Monobasic. 

 Nascent hydrogen converts it into glyceric acid ; hy- 

 driodic acid at 200 into pyrotartaric acid. 



C. BIBASIC, TKIATOMIC ACIDS, C n H 2n ~ 2 5 . 



1. Tartronic Acid (Oxymalonic Acid). 

 OH 



C 3 H 4 5 =CHJ 



(CO.OH) 2 . 



Formation. By spontaneous evaporation of an aque- 

 ous solution of nitrotartaric acid ; by the action of 

 nascent hydrogen on mesoxalic acid ; and probably also 

 by boiling grape-sugar with an alkaline solution of 

 copper oxide. 



Properties. Large, colorless prisms, which fuse at 

 175 and are resolved at this temperature into water, 

 carbonic anhydride, and glycolid (p. 146). 



2. Malic Acid (Oxysuccinic Acid). 

 COTO.. .CO.OH 



Occurrence. Is very widely distributed throughout 

 the vegetable kingdom ; partially united with metals, 

 as, for instance, with potassium in sweet cherries, par- 

 tially in a free state, as in the juice of unripe apples, 

 unripe grapes, the berries of mountain-ash, etc. 



Formation and preparation. By boiling monobrom- 

 succinic acid with water and silver oxide ; by the 

 action of nitrous acid on asparagine. Most practicably 

 prepared from the berries of mountain-ash which are 



