476 CONSIDERATION OF CARBON COMPOUNDS. 



CHC1 3 + O = COC1 2 -f- HC1. 



Chloroform containing some alcohol is less apt to undergo this oxida- 

 tion, but the latter also takes place when chloroform is used for inha- 

 lation near an exposed flame. 



Analytical reactions for chloroform. 



1. Dip a strip of paper into chloroform and ignite. The flame has 

 a green mantle and emits vapors of hydrochloric acid, rendered more 

 visible upon the approach of a glass rod moistened with ammonia water. 



2. Add a drop of chloroform and a drop of aniline to some alco- 

 holic solution of potassium hydroxide and heat gently : a peculiar, 

 penetrating, offensive odor of benzo-isonitrile, C 6 H 5 NC, is noticed. 

 (Chloral shows the same reaction.) 



CHClg -f 3KOH + C 6 H 5 .NH 2 = C 6 H 5 NC + 3KC1 + 3H 2 O. 



3. Add some chloroform to Fehling's solution and heat : red 

 cuprous oxide is precipitated. 



4. Vapors of chloroform, when passed through a glass tube heated 

 to redness, are decomposed into carbon, chlorine, and hydrochloric 

 acid. The two latter should be passed into water, and may be recog- 

 nized by their action on silver nitrate (white precipitate of silver 

 chloride) and on mucilage of starch, to which potassium iodide has 

 been added (blue iodized starch is formed). 



5. Heat some chloroform with solution of potassium hydroxide and 

 a little alcohol. Chloroform is decomposed into potassium chloride 

 and formate : 



CHC1 3 -f 4KOH == 3KC1 + KCH0 2 + 2H 2 O. 



Divide solution into two portions. Acidulate one portion with 

 nitric acid, boil, and add silver nitrate : white precipitate of silver 

 chloride. To second portion add a little ammonia water and a crystal 

 of silver nitrate : a mirror of metallic silver will be formed after 

 heating slightly. 



6. Add to 1 c.c. of chloroform about 0.3 gramme of resorcin in 

 solution, and 3 drops of solution of sodium hydroxide ; boil strongly : 

 a yellowish-red color is produced, and the liquid shows a beautiful 

 yellow-green fluorescence. (Chloral shows the same reaction.) 



In cases of poisoning chloroform is generally to be sought for in the lungs 

 and blood, which are placed in a flask connected with a tube of difficultly 

 fusible glass. By heating the flask the chloroform is expelled and decomposed 

 in the heated glass tube, as stated above in reaction 4. Another portion of 

 chloroform should be distilled without decomposing it, and the distillate tested 

 as above stated. 



There is no chemical antidote which may be used in cases of poisoning by 



