Dichloromethane ( CH2Cl2 ) is widely used as a solvent , as a propellant in aerosols . Direct contact of dichloromethane in humans causes intense burning and milk redness of the skin .
Trihalogen Derivatives 1 . Chloroform [ Trichloromethane , CHCl 3 ] Methods of preparation
Properties 1 . Oxidation of CHCl 3 gives poisonous gas phosgene ( carbonyl chloride ).
To avoid this oxidation CHCl 3 iI . toreci in dark brown bottles and filled to the brim . 1 % ethanol is added to chloroform which converts harmful phosgene gas into diethyl carbonate .
2 . CHCl 3 is widely used in the production of freon refrigerant R-22 .
3 . On nitration , it gives tear producing insecticide substance chloropicrin .