158 RESK ARCHES UPON THE CHEMICAL PROPERTIES OP GASES. 



traces of hydrogen. The following explanation of the reaction is given by the 

 authors cited : 



^1 A- (Cu). 

 CH3I + Zn (Cu) + H2O = CH, + Zn: Z^ 



~~"0H. 



200 c.c. of the methane so prepared were burned, and the products aspirated through 

 soda solution. On testing: the latter for haloo^en, no traces could be found. From 

 this it was evident that no vapor of methyl iodide had escaped decomposition by the 

 zinc. Methane is obtained when chloroform dissolved in alcohol is dropped upon 

 zinc powder. 



CH3CI 4- 3 H,0 + 6 Zn = 3 ZnO + 3 ZnC!^ + 2 CH^ 



(SabanejefF, Ber.^ IX, p. 1810). This method was found to give very satisfactory 

 results. The process usually given in the text-books, by heating acetate of soda 

 with alkali, is very unsatisfactory both as regards purity and quantity of product. 

 Expt. 9. Palladium Asbestos. — 



Methane 3.1 



Air 96.9 



Oxidation to CO2 occurred at the following temperatures : 



(1) Above melling point of Cdl, (404°). 



(2) " " " '• Cdlj (404O). 



(3) • " Ba (CIO3), (4140). 



(4) " '■ " " Cdlj. 



(5) " " '• " Ba (CIO3), (4140). 



In the above trials methane from methyl iodide was used. 



The preceding experiment was repeated, using methane from chloroform. In 

 six diiferent trials the temperature of oxidation was found to be between the melting 

 points of Cdfa and AgCl (404° to 451°). In one trial, oxidation occurred consid- 

 erably above the melting point of AgCl. 



The temperature of oxidation of methane is therefore extremely high as com- 

 pared with that of hydrogen. 



Hempel, in his excellent work on gas analysis, says that methane prepared from 

 sodium acetate is oxidized by palladium at 210°. My results do not confirm this 

 statement. The difference is possibly due to impurities in the methane. 



JExpt. 10. Palladium- Platinum Asbestos, — 



Air 96.9 



Methane 3. 1 



Asbestos was moistened alternately with palladium chloride and platinum chloride 

 and the metals reduced by burniiig alcohol, as already described, the object being to 



