318 CONSIDERATION OF CARBON COMPOUNDS. 



2. Heated with silver nitrate and ammonium hydroxide a silver- 

 mirror is formed on the glass. 



3. Heated with Fehling's solution a red precipitate is formed. 

 See also reactions 2 and 6 for chloroform below. 



Chloroform, Chloroformum, CHC1 3 = 119.2 (Trichlormeihane, 

 Dichlormethyl chloride). When either chlorine, bromine, or iodine is 

 allowed to act upon methane, CH 4 , a number of substitution products 

 are formed. Thus, if methane is considered as methyl hydride, 

 CH 3 H, the first product of substitution is methyl chloride, CH 3 C1 ; 

 the second is monochlor methyl chloride, CH 2 C1C1 ; the third is 

 dichlormethyl chloride or chloroform, CHC1 2 C1 ; and the fourth is 

 carbon tetrachloride, CC1 4 . Similar products are formed by the 

 action of iodine or bromine upon methane, or, in fact, upon any of 

 the paraffins. 



Chloroform is, however, not obtained for commerce by the above 

 process, but by the action of bleaching-powder and calcium hydroxide 

 on alcohol. The three substances named, after being mixed with a 

 considerable quantity of water, are heated in a retort until distilla- 

 tion commences ; the crude product of distillation is an impure chloro- 

 form, which is purified by mixing it with strong sulphuric acid and 

 allowing the mixture to stand ; the upper layer of chloroform is 

 removed and treated with sodium carbonate (to remove any acids) 

 and distilled over calcium oxide (to remove water). 



The explanation of the formation of chloroform by the above process ha* 

 indirectly been given in connection with the consideration of chloral, where it 

 has been shown that alcohol is converted by the action of chlorine first inta 

 aldehyde and subsequently into chloral, which, upon being treated with 

 alkalies, is decomposed into an alkali formate and chloroform. 



The action of the chlorine of the calcium hypochlorite (which is the active 

 principle in bleaching-powder) upon the alcohol is similar to that of free 

 chlorine upon alcohol; in both cases aldehyde, and afterward chloral, are 

 formed, which latter, in the manufacture of chloroform, is decomposed by the 

 calcium hydroxide into chloroform and calcium formate. The last-named salt 

 is, however, not found in the residue of the distillation, because it is decomposed 

 by bleaching-powder and calcium hydroxide into calcium carbonate, chloride, 

 and water : 



Ca(CHO 2 ) 2 + Ca(ClO) 2 + Ca(OH) 2 = 2CaCO 3 + CaCl 2 + 2H 2 O. 



If the various intermediate steps of the decomposition are not considered, the 

 process may be represented by the following equation : 



4C 2 H 6 + 8CafC10) 2 == 2CHC1 3 -f- 3[Ca(CHO 2 ) 2 ] + 5CaCl 2 + 8H 2 O. 

 Alcohol. Calcium Chloroform. Calcium Calcium Water, 



hypochlorite. formate. chloride. 



