ALDEHYDES. HALOID DERIVATIVES. 319 



Chloroform is now made extensively by the action of bleaching-powder upon 

 acetone ; the reaction takes place thus : 



2CO(CH 3 ) 2 -f- 3Ca(C10) 2 = 2CHC1 3 + 2Ca(OH) 2 + Ca(C 2 H 3 O 2 ) 2 . 

 Acetone. Calcium Chloroform. Calcium Calcium 



hypochlorite. hydroxide. acetate. 



Pure chloroform is a heavy, colorless liquid, of a characteristic 

 ethereal odor, a burning, sweet taste, and a neutral reaction ; it is but 

 very sparingly soluble in water, but miscible with alcohol and ether 

 in all proportions ; the specific gravity of pure chloroform is 1.50, 

 but a small quantity of alcohol (from one-half to one per cent.), 

 allowed to be present by the U. S. P., causes the specific gravity to 

 be about 1.488; boiling-point 62 C. (143 F.), but rapid evapora- 

 tion takes place at all temperatures. 



Chloroform should be tested for excess of alcohol by specific gravity ; for 

 hydrochloric acid and chlorine by shaking it with water, which afterward 

 should not give a precipitate with silver nitrate ; for aldehyde by heating with 

 solution of potassium hydroxide, which should not be colored brown; for 

 empyreumatic and other organic compounds by shaking with an equal volume 

 of pure sulphuric acid, which should remain colorless; or by evaporation, 

 when no residue should be left and no odor should be perceptible after the 

 chloroform has been volatilized. 



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 water of 

 ammonia. 



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-isonitril, C 6 H 5 NC, is noticed. 

 (Chloral shows the same reaction.) 



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 

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

 been added (blue iodized starch is formed). 



