RESEARCHES UPON THE CHEMICAL PROPERTIKS OF GASES. 197 



plete. Agitation with the solution is quite necessary in order to insure complete 

 absorption. Wagner (Ber., 1888, p. 3343) has shown that the higher acetylenes, 

 like the olefines, are converted by neutral potassium permanganate solution into 

 hydroxyl compounds. 



The various classes of hydrocarbons of the fatty series possess in common a 

 high resistance to destructive oxidation by oxidizing agents, yielding in some cases 

 hydroxyl compounds but rarely CO2. This is true also of benzene, which is changed 

 by potassium jDermanganate into oxalic acid and formic acid (Bernthsen, p. 326). 



SULPHUR COMPOUNDS. 

 CARBON OXTSULPHIDE. 



This gas was prepared b}"" the method of Klason {Ber., 1887, p. 55 R, and 

 J. Pr. Ch., Yol. XXXYI, p. 61). To a cold mixture of 290 c.c. sulphuric acid and 

 400 c.c. of water, 50 c.c. of a saturated solution of sulphocyanide of potassium was 

 gradually added, the mixture being warmed to 30°. The gas was evolved in a 

 steady stream and was purified by passage (1) through 20 per cent, potash solution, 

 (2) through 25 per cent, solution of aniline in alcohol, (3) through broken ice. 



COS was also prepared by the action of carbon disulphide on alumina at a high 

 temperature (Gautier, Compt. Bend., CYII, p. 911). The gas, if dry, may be pre- 

 served over mercury. Contact with water causes a change into carbon dioxide and 

 hydrogen sulphide. Caustic soda solution is changed into a. mixture of sodium sul- 

 phide and carbonate. The constant tendency to decomposition renders it impossible 

 to preserve the gas over water without loss. In trying its I'eactions, it was found 

 necessary to conduct the gas immediately before use into some substance specially 

 adapted to absorb hydrogen sulphide. For the absorption of H2S, Fresenius recom- 

 mends pumice saturated with copper sulphate solution and dried (Fresenius, Quant. 

 Arialyse, 6te Auflage). In a series of trials with this and other absorbents, precipi- 

 tated oxide of mercury was found to answer best. Dampened absorbent cotton is 

 coated with the yellow powder by rubbing with a large pestle. This preparation, used 

 dry in a long glass tube, completely removes HoS but exerts no action upon COS. 



1. Reactions in Solution. 



REAGENTS. KEACTIONS. 



Palladium chloride Prompt precipitation. Precipitate is brownish black 



and flocculent. 



Platinum chloride Black precipitate. 



Gold chloride Rapidly darkens. An olive-brown precipitate collects. 



Copper sulphate Black precipitate, which forms very slowly. 



Ammoniacal copper sulphate Black precipitate, forming promptly. 



A. P. S. — TOL, XTTL Z. 



