When chloroform [CHCL3 ] is left exposed to air and light,it slowly gets oxidized to phosgene gas or carbonyl chloride [COCL3] Which is a poisinous gas.
2CHCL3+ O2 –> 2COCL2+2HCL
it is used as anesthetic purpose in surgery. Hence anesthetic chlorform is kept in brown bottle to cut off light and the bottle is filled completely with chloroform to exclude air. A 1% solution of ethyl alcohol is also added to it to retard oxidation of chloroform. Ethanol converts phosgene to non poisonous diethyl carbonate.
uses of chloroform
- It is used as laboratory reagent
- It is used as preservative for biological specimesns
- It is used as anesthic in surgical operation
- It is used to prepare organic compound like poisons chloropicrin,salicylic acid etc.
Why does itnot give white precipitate with aqueous silver nitrate
it is non polar covalent compound and doesnot give white ppt with silver nitrate solution. Only polar compound like HCL or NAcl give the white ppt with silver nitrate.
If chloroforms is impure it may conatin hcl as impurity and gives the test of silver nitrate solution.