Chemical properties of trichloromethane are:
Phosgene is extremely poisonous gas. To use chloroform as an anaesthetic agent, it is necessary to prevent the above reaction. The following two precautions are taken when chloroform is stored.
(a) It is stored in dark blue or brown coloured bottles, which are filled upto the brim.
(b) 1% ethyl alcohol is added. This retards the oxidation and converts the phosgene
formed into harmless ethyl carbonate.
Formation of Tear Gas
Nitration : The hydrogen of the chloroform is replaced by nitro group when it is treated with concentrated nitric acid. The product formed is chloropicrin or trichloronitro methane or nitro chloroform. It is a liquid, poisonous and used as an insecticide and a war gas.
Reimer-Tiemann reaction :
Carbylamine reaction(Isocyanide test) : This reaction is actually the test of primary amines. Chloroform, when heated with primary amine in presence of alcoholic potassium hydroxide forms a derivative called isocyanide which has a very offensive smell.
This reaction is also used for the test of chloroform.
(i) It is used as a solvent for fats, waxes, rubber, resins, iodine, etc.
(ii) It is used for the preparation of chloretone (a drug) and chloropicrin (Insecticide).
(iii) It is used in laboratory for the test of primary amines, iodides and bromides.
(iv) It can be used as anaesthetic but due to harmful effects it is not used these days for this purpose.
(v) It may be used to prevent putrefaction of organic materials, i.e., in the preservation of anatomical species.
Tests of chloroform
(i) It gives isocyanide test (Carbylamine test).
(iii) Pure Chloroform does not give white precipitate with silver nitrate