Write a note on DDT.

Explanation

DDT, the first chlorinated organic insecticides, was originally prepared in 1873, but it was not untill 1939 that Paul Muller of Geigy Pharmaceuticals in Switzerland discoveredthe effectiveness of DDT as an insecticide. Paul Muller was awarded the Nobel Prize in Medicine and Physiology in 1948 for this discovery.

It is prepared by condensation of chloral with chlorobenzene in presence of sulpuric acid.
DDT is a powerful insecticides. It is very effective against the mosquito that spreads malaria and like that carries typhus.
Many species of insects developed resistance to DDT. It has high toxicity towards fish.
It is chemically stable and fat soluble.
It is not readily metabolised by animals and is stored in a fat tissues. If ingestion continues at a steady rate, DDT builds up within the animal over time.
The use of DDT was banned in the United States in 1973, although it is still in use in some other parts of the world.