ALDEHYDES. HALOID DERIVATIVES. 317 



duct separates into two layers ; the lower is removed and shaken with 

 three times its volume of strong sulphuric acid and distilled, the dis- 

 tillate is mixed with calcium oxide and again distilled ; the portion 

 passing over between 94 and 99 C. (201 and 210 F.) is collected. 

 The decomposition taking place between alcohol and chlorine may 

 be explained by the formation of aldehyde : 



C 2 H 6 + 2C1 = C 2 H 4 + 2HC1, 



and by the subsequent replacement of hydrogen by chlorine : 

 C 2 H 4 O -f 6C1 = C 2 HC1 3 -f 3HC1 



The actual decomposition is, however, somewhat more complicated, 

 numerous other products being formed at the same time. By treat- 

 ment with sulphuric acid these other substances are removed. 



Chloral is a colorless, oily liquid, having a penetrating odor and an 

 acrid, caustic taste; its specific gravity is 1.5, and its B. P. 95 C. 

 (202 F.). 



Chloral hydrate, Chloral, U. S. P., C 2 HC1 3 O.H 2 O=165.2. When 

 water is added to chloral the two substances combine, heat is dis- 

 engaged, and the hydrate of chloral is formed, which is a crystalline, 

 colorless substance, having an aromatic, penetrating odor, a bitter, 

 caustic taste, and a neutral reaction ; it is freely soluble in water, 

 alcohol, and ether, also soluble in chloroform, carbon disulphide, 

 benzene, fatty and essential oils, etc. ; it liquefies when mixed with 

 carbolic acid or with camphor; it melts at 58 C.(136 F.), and boils 

 at 95 C. (203 F.), and also volatilizes slowly at ordinary temperature. 



Chloral, and its hydrate, are decomposed by weak alkalies into 

 chloroform and a formate of the alkali metal : 



C 2 HC1 3 + KHO KCHO 2 + CHC1 3 . 



Chloral. Potassium Potassium Chloroform, 



hydroxide. formate. 



This decomposition was believed to take place in the animal body, and 

 especially in the blood, whenever chloral was given internally, but recent in- 

 vestigations seem to contradict this assumption. There is no chemical antidote 

 which may be used in cases of poisoning by chloral, and the treatment is, 

 therefore, confined to the use of the stomach-pump and to the maintenance of 

 respiration. 



Analytical reactions for chloral. 



1. Chloral or chloral hydrate heated with potassium hydroxide is 

 converted into potassium formate and chloroform, which latter may 

 be recognized by its odor. (See explanation above.) 



