132 ACETYLENE SERIES. 



Properties. Colorless gas; somewhat soluble in water; 

 of a characteristic unpleasant odor; burns with a very 

 luminous flame. It is absorbed in large quantity by 

 an ammoniacal solution of copper subchloride ; the 

 resulting red precipitate, which is exceedingly explo- 

 sive and evolves pure acetylene gas when hydrochloric 

 acid is poured upon it, is cuprosoacetyl oxide (C 2 CuH) 2 0. 

 In an ammoniacal solution of silver, it produces a 

 white precipitate with similar properties. By the aid 

 of this property acetylene can be separated from other 

 gases and prepared in a pure condition. By the action 

 of nascent hydrogen (when the copper compound is 

 brought in contact with zinc and ammonia) it is trans- 

 formed into ethylene. 



Acetylene diehloride, C 2 H 2 C1 2 . Cannot be pre- 

 pared by direct action. Acetylene detonates when 

 brought in contact with chlorine gas. Acetylene is 

 entirely absorbed by antimony chloride (SbCl 5 ), large 

 crystalline laminae C 2 H 2 .SbCl 5 being formed, which, 

 when heated, are resolved into antimony terchloride 

 (SbCl 3 ) and acetylene diehloride. Colorless liquid; 

 boiling point, 55. Is decomposed when heated to 

 360, yielding carbon and hydrochloric acid; when 

 heated with alcoholic potassa to 100, it yields potas- 

 sium chloride and acetate. 



Acetylene tetrachloride, C 2 H 2 C1 4 . Is formed when 

 the compound C 2 H 2 .SbCl 5 is distilled with an excess of 

 antimony chloride. Colorless liquid, boiling at 147. 



Acetylene unites directly with bromine, forming 

 C 2 II 2 Br 2 and C 2 H 2 Br 4 . Both compounds are liquids. 

 "When heated with iodine to 100, it yields a crystal- 

 line iodide C 2 H 2 I 2 , fusing at about 70. It combines 

 with hydriodic acid, forming liquid compounds: C 2 H 3 I, 

 boiling point, 62, and C 2 H 4 I 2 , boiling point, 182. 

 The latter compound is isomeric with ethylene iodide. 



2. Allylene, C 3 H 4 , is produced by the action of sodium 

 ethylate on monochlor- or monobrornpropylene, and by 



