Give the uses of freon 12, DDT, carbon tetrachloride and iodoform.

Explanation

lodoform: It was earlier used as an antiseptic but the antiseptic properties are due to the liberation of free iodine and not due to iodoform itsdf. Due to its objectionable smell, it has been replaced by other formulations containing iodine.
Carbon tetrachloride:
Uses:
(i) As an industrial solvent for oil, fats resins etc. and also in dry cleaning.
(ii) `C Cl_(4)` vapours are highly non inflammable, thus `C Cl_(4)` is used as a fire extinguisher under the name pyrene.
Freons: Freon-12 `(C Cl_(2)F_(2))` is most common freons in industrial use.
Uses: For aerosol propellants, refrigeration and air conditioning purposes.
DDT (p -p' - Dichloro diphenyl - trichloro ethane):
(i) The use of DDT increased enormously on a world basis after World War ll, Primarily because of its effectiveness against the mosquitoes that spreads malaria and other insects which damages crops.
(ii) However, problems related to extensive use of DDT began to appear in the late 1940 s. Many species of insects developed resistance to DDT, it was also discovered to have a high toxicity towards fishes. DDT is not metabolised very rapidly by animals, instead it is deposited and stored in the fatty tissues. If the ingestion continues at a steady rate, DDT builds up within the animals overtime.