Question
Write a note on DDT.
✓
Answer
→ DDT, the first chlorinated organic insecticides, was originally prepared in 1873, but it was not until 1939 that Paul Muller of Geigy Pharmaceuticals in Switzerland discovered the effectiveness of DDT as an insecticide.
→ Paul Muller was awarded the Nobel Prize in Medicine and Physiology in 1948 for this discovery.
→ The use of DDT increased enormously on a worldwide basis after world war II, primarily because of its effectiveness against the mosquito that spreads malaria and lice that carry typhus.
→ However, problems related to extensive use of DDT began to appear in the late 1940s.
→ Many species of insects developed resistance to DDT, and it was also discovered to have a high toxicity towards fish.
→ The chemical stability of DDT and its fat solubility compounded the problem.
→ DDT is not metabolised very rapidly by animals; instead, it is deposited and stored in the fatty 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.
→ Paul Muller was awarded the Nobel Prize in Medicine and Physiology in 1948 for this discovery.
→ The use of DDT increased enormously on a worldwide basis after world war II, primarily because of its effectiveness against the mosquito that spreads malaria and lice that carry typhus.
→ However, problems related to extensive use of DDT began to appear in the late 1940s.
→ Many species of insects developed resistance to DDT, and it was also discovered to have a high toxicity towards fish.
→ The chemical stability of DDT and its fat solubility compounded the problem.
→ DDT is not metabolised very rapidly by animals; instead, it is deposited and stored in the fatty 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.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
What is spectrochemical series? Explain the difference between a weak field ligand and a strong field ligand.
In a reaction between $A$ and $B$, the initial rate of reaction $(r_0)$ was measured for different initial concentrations of $A$ and $B$ as given below:
What is the order of the reaction with respect to $A$ and $B?$
→| $A/mol L^{-1}$ | $0.20$ | $0.20$ | $0.40$ |
| $B/mol L^{-1}$ | $0.30$ | $0.10$ | $0.05$ |
| $r_0/mol L^{-1} s^{-1}$ | $5.07 \times 10^{-5}$ | $5.07 \times 10^{-5}$ | $1.43 \times 10^{-4}$ |
[Fe(CN)6]4- and [Fe(H2O)6]2+ are of different colours in dilute solutions. Why?
The equilibrium constant of cell reaction :
$Sn^{4+}(.aq) + Al(s) Al^{3+ }\rightarrow + Sn^{2+} (aq)$ is $4.617 \times 10^{184}, at 25 ^\circ C$
a. Calculate the standard emf of the cell. $($Given: $\log 4.617 \times 10^{184} = 184.6644)$
b. What will be the $E^\circ$ of the half cell $Al^{3+}/Al, if E^\circ$ of half cell $Sn^{4+}/Sn^{2+}$ is $4+ 0.15 V.$
→$Sn^{4+}(.aq) + Al(s) Al^{3+ }\rightarrow + Sn^{2+} (aq)$ is $4.617 \times 10^{184}, at 25 ^\circ C$
a. Calculate the standard emf of the cell. $($Given: $\log 4.617 \times 10^{184} = 184.6644)$
b. What will be the $E^\circ$ of the half cell $Al^{3+}/Al, if E^\circ$ of half cell $Sn^{4+}/Sn^{2+}$ is $4+ 0.15 V.$
- What is the basis of formation of the spectro $-$ chemical series?
- Draw the structures of geometrical isomers of the following coordination
- complexes:$\ce{[Co(NH_3)_3Cl_3]}$ and $\ce{[CoCl_2(en)_2]^+}.$
- $($ en $=$ ethylenediamine and atomic number of $Co$ is $27).$
- What type of isomerism is shown by the complex $\ce{[Co(NH_3)_6] [Cr(CN)_6]}$?
- Why a solution of $\ce{[Ni(H_2O)_6]^{2+}}$ is green while a solution of $\ce{[Ni(CN)_4]^{2–}}$ is colourless? $($At. no. of $Ni = 28)$
- Write the $\text{IUPAC}$ name of the following complex: $\ce{[Co(NH_3)_5(CO_3)]Cl}$.
What do you understand by the term 'conductance'? What are its units?
For the reaction:
$2 A+B \rightarrow A_2 B$
the rate $= k [ A ][ B ]^2$ with $k =2.0 \times 10^{-6} mol^{-2} L^2 s^{-1}$. Calculate the initial rate of the reaction when $[ A ]=0.1 mol$ $L ^{-1},[B]=0.2 mol L ^{-1}$. Calculate the rate of reaction after $[ A ]$ is reduced to $0.06 mol L ^{-1}$.
→$2 A+B \rightarrow A_2 B$
the rate $= k [ A ][ B ]^2$ with $k =2.0 \times 10^{-6} mol^{-2} L^2 s^{-1}$. Calculate the initial rate of the reaction when $[ A ]=0.1 mol$ $L ^{-1},[B]=0.2 mol L ^{-1}$. Calculate the rate of reaction after $[ A ]$ is reduced to $0.06 mol L ^{-1}$.
- Deficiency of which vitamin causes scurvy?
- What type of linkage is responsible for the formation of proteins?
- Write the product formed when glucose is treated with HI.
Differentiate between order and molecularity of a reaction.