State the various uses of :
$(i)$ Dichloromethane (Methylene chloride)
$(ii)$ Trichloromethane (Chloroform)
$(iii)$ Tri-iodomethane (Iodoform)
$(iv)$ Tetrachloromethane (Carbon tetrachloride)
$(v)$ Freons

(N/A) $(i)$ Dichloromethane $(CH_{2}Cl_{2})$: It is used as a propellant in aerosols,and as a process solvent in the manufacture of drugs. It is also used as a metal cleaning and finishing solvent.
$(ii)$ Trichloromethane $(CHCl_{3})$: Chloroform is employed as a solvent for fats,oils,alkaloids,iodine,and other substances. The major use of chloroform is in the production of refrigerant Freon $R-22$.
It was once used as a general anaesthetic in surgery but has now been replaced by less toxic,safer anaesthetics such as ether.
$(iii)$ Tri-iodomethane $(CHI_{3})$: It was used earlier as an antiseptic,but the antiseptic properties are due to the liberation of iodine and not due to iodoform itself.
Due to its objectionable smell,it has been replaced by other formulations containing iodine.
$(iv)$ Tetrachloromethane $(CCl_{4})$: It is used as feedstock in the synthesis of chlorofluorocarbons and other chemicals,pharmaceutical manufacturing,and general solvent use.
It is produced in large quantities for use in the manufacture of refrigerants and propellants for aerosol cans.
Until the mid $1960$s,it was widely used as a cleaning fluid,both in industry as a degreasing agent and in the home as a spot remover and as a fire extinguisher.
$(v)$ Freons: These are used as aerosol propellants,and for refrigeration and air conditioning purposes.
The chlorofluorocarbon compounds of methane and ethane are collectively known as freons.
They are extremely stable,unreactive,non-toxic,non-corrosive,and easily liquefiable gases.
Freon $12$ $(CCl_{2}F_{2})$ is one of the most common freons in industrial use. It is manufactured from tetrachloromethane by the Swarts reaction.