Paul Muller of Geigy Pharmaceuticals in Switzerland discovered the insecticidal effectiveness of DDT in 1939. He was awarded the Nobel Prize in Medicine and Physiology in 1948 for this discovery.

Freons released into the atmosphere, including those used in refrigeration, eventually reach the stratosphere. In the stratosphere, freons can initiate radical chain reactions that disturb the natural ozone balance, posing a significant environmental concern related to ozone layer depletion.

Freon 12 is manufactured from tetrachloromethane using the Swarts reaction. Freons are widely used in industrial applications for aerosol propellants, refrigeration, and air conditioning.

Freons are chlorofluorocarbon compounds of methane and ethane. They are stable, unreactive, non-toxic, non-corrosive, and easily liquefiable gases. Freon 12 (CCl₂F₂) is a common industrial freon used in refrigeration and air conditioning, produced from tetrachloromethane by the Swarts reaction.

Carbon tetrachloride, when released into the air, rises to the atmosphere and contributes to ozone layer depletion. This depletion is associated with increased human exposure to ultraviolet rays, potentially leading to skin cancer, eye diseases, immune system disorders, and other ...