Introduction 

Iodoform, commonly known as triiodomethane CHI3, is a yellow crystalline substance. It is water-insoluble but soluble in solvents such as ethanol, chloroform, and ether. When handled with an aqueous sodium hydroxide solution, it is hydrolysed, yielding sodium methanoate (sodium formate).

Freons are chlorofluorocarbon compounds derived from methane and ethane. The term “chlorofluorocarbon compounds” refers to chemicals that are primarily composed of carbon, fluorine, and chlorine. Because of their low boiling temperatures, surface tension, and viscosity, they are particularly useful refrigerants. They are inert, extremely stable chemicals. In the refrigerating and air-conditioning systems, Freons provide no fire risk and emit no noticeable odour. Freon 12 (Dichlorodifluoromethane), Freon 11 (trichlorofluoromethane), Freon 22 (chlorodifluoromethane), dichlorotetrafluoroethane (Freon 114), and Freon 113 have been the most important members of the group (trichlorotrifluoroethane).

DDT (p,p’-Dichlorodiphenyltrichloroethane) is an insecticide that is colourless, crystalline, tasteless, and almost odourless.

Body

Uses of Iodoform

• Because of the liberation of free iodine, they are used as an antiseptic. It’s not because of the iodoform.

• However, due to the unpleasant odour, it was replaced by other iodine-containing solutions.
• It is an active ingredient in many ear powders for dogs and cats, along with zinc oxide and propionic acid, and is used to prevent infection and make ear hair removal easier.

Uses of Freons (CFCs)

Following are the uses of Ferons: 

• Freon 12 (CCl2F2) is the most common Freon used in industry.
• Swarts reaction is used to create freons from tetrachloromethane.
• Freons are used as propellants in aerosols and air conditioners. Also, freons are used as refrigerants. 
• Freons have also been widely used as propellants in aerosols and foams for deodorants, detergents, shaving creams, hairsprays, and insecticides.

Uses of DDT(p,p’-Dichlorodiphenyltrichloroethane)

• DDT was the first chlorinated organic pesticide found in 1873, which was then investigated further. Paul Muller discovered the use of DDT as an insecticide in 1939.
• It is highly toxic to all living species since it is not quickly digested by animals and is accumulated and stored in fatty tissues.

Environmental Effects of Iodoform-freons and DDT

Elevated amounts of iodoform-freons are hazardous to both the environment and human life. High amounts of Iodoform exposure can cause nausea and dizziness, as well as harm to the central nervous system, the heart, kidneys, and liver, as well as depression.

Freons have an impact on the ozone layer in the atmosphere. It is commonly referred to as a CFC. Its production was banned in numerous nations, including the United States, in 1994. Freons cause radical chain reactions that deplete the ozone layer. It disrupts the atmosphere’s equilibrium point. When exposed to high concentrations of Freon gases, one loses concentration and coordination. It is not a carcinogen, mutagen, or teratogen, and it has no long-term health impacts. Children are more vulnerable to freons than adults. However, because Freon is a substantial polluter of the environment, its use in modern appliances has been taken out.

DDT is a long-lasting organic pollutant that is easily absorbed by soils and sediments, acting as sinks and long-term sources of exposure for organisms. DDT can bioaccumulate due to its lipophilic characteristics, particularly in predatory birds. DDT is poisonous to a vast number of living organisms, including sea creatures such as crayfish, daphnids, sea shrimp, and many fish species.

Conclusion

Iodoform, freons and DDT are polyhalogen compounds. Iodoform, commonly known as triiodomethane CHI3, is a yellow crystalline substance. It is water-insoluble but soluble in solvents such as ethanol, chloroform, and ether. Freons are chlorofluorocarbon compounds derived from methane and ethane. The term “chlorofluorocarbon compounds” refers to chemicals that are primarily composed of carbon, fluorine, and chlorine.DDT (p,p’-Dichlorodiphenyltrichloroethane) is an insecticide that is colourless, crystalline, tasteless, and almost odourless. Iodoform, freons and DDT are useful in industry and agriculture. Elevated amounts of iodoform-freons and DDT are hazardous to both the environment and human life.