Question

Which of the following is an insecticide?
(A) Bakelite.
(B) Aspirin.
(C) DDT.
(D) TNT.

Answer 1

Hint : We know that the DDT was synthesized for the first time in $1874$ by an Austrian chemist Othmar Zeidler. But it was only in $1939$ that a Swiss chemist Paul Hermann discovered its use as an insecticide. DDT has a great significance in world history.

Complete Step By Step Answer:
DDT (dichlorodiphenyltrichloroethane) is an organochlorine insecticide which is a colorless, crystalline solid, tasteless and almost odourless chemical compound. Trinitrotoluene ( $2,4,6-trintrotoluene$ TNT) is an extensively used explosive, which has been detected in soil and water at military sites and at munitions manufacturing and training operations. DDT is now banned due to high levels of toxicity and deaths of people due to high dosage. It is bio-accumulative and the quantity magnifies as we go higher up in the food chain.
A result of this was a sudden drop in the number of vultures that fed on dead carcasses of animals. This severely upset the food chain and the consequences can still be seen. In World War $II$ when the world was engulfed in war, diseases like malaria wreaked havoc among the soldiers and civilians. So DDT came as a potential solution to reduce the number of mosquitos (the vectors for malaria causing pathogens). There are many uses of DDT, especially as an insecticide and pesticide. Initially, during WW $II$ it was also used to control illnesses like typhus, body lice, and malaria. DT became available for public sale in $1945$ for use as an agricultural pesticide and household insecticide.
By $1944$ we started hearing concerns that excessive use of DDT might do more harm than good. It was reported that excessive use of DDT can not only kill insects but also kills fish, birds and other forms of life. This shows that DDT is basically an insect and mosquito repellent as it was used to combat insect borne diseases. It was also used to control the bubonic plague. In areas that had such epidemics, an airplane flew over the region and sprayed large quantities of DDT in the surrounding area.
Therefore, the correct answer is option C.

Note :
Remember that the DDT should be handled carefully, as DDT can disturb the endocrine system of humans. It is also considered as a carcinogen (substances that can potentially cause the formation of cancerous cells). In case of shorter periods of time it does not harm that much and is classified by the US National Toxicology Program as moderately toxic.