CBSE 12th Standard Chemistry Subject Haloalkanes and Haloarenes Value Based Questions 3 Mark Questions With Solution 2021
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CBSE 12th Standard Chemistry Subject Haloalkanes and Haloarenes Value Based Questions 3 Mark Questions With Solution 2021
12th Standard CBSE
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Reg.No. :
Chemistry
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Trichloromethane or chloroform is a colorless oily liquid with a peculiar smell.It is sparingly soluble in water.The vapor when enhaled cause unconsciousness and therefore, it is used as an anesthetic.
Answer the following questions:
(i) What happens when chloroform is not protected from oxygen during its storage?
(ii) Why is the use of chloroform as an anesthetic has been reduced?(a) -
D.D.T is one of the most powerful insecticides which is effective against the mosquitoes that spread malaria. Mukesh's mother wanted to buy D.D.T from the market to use at night to protect her family from mosquitoes. But Mukesh stopped his mother from purchasing D.D.T.
(a) How did Mukesh convince her mother for not using D.D.T at night?
(b) What values are attached to suggestion of Mukesh?(a)
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CBSE 12th Standard Chemistry Subject Haloalkanes and Haloarenes Value Based Questions 3 Mark Questions With Solution 2021 Answer Keys
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(i) In the presence of air and light, chloroform is oxidized to poisonous gas phosgene.
\(CHC{ l }_{ 3 }+\frac { 1 }{ 2 } { O }_{ 2 }\overset { Air\quad or\quad light }{ \longrightarrow } \quad COC{ l }_{ 2 }+HCl\\ Phosgene\)
(ii) Continuous chloroform exposure may damage liver and kidneys because chloroform is metabolised to poisonous phosgene. Some people develop sores when the skin comes in contact with chloroform for a long time. Therefore, use of chloroform as an anesthetic has been replaced by less toxic and safer anesthetic such as ether. -
(a) Though D.D.T is a very powerful insecticide for mosquitoes, yet the excessive use of D.D.T has many problems. The use of D.D.T has the following disadvantages:
(i) Many species of insects develop resistance to D.D.T.
(ii) It has a high toxicity towards fish.
(iii) The chemical stability of D.D.T and its fat solubility has problems.
(iv) It is not biodegradable and its residues accumulate in environment and its long term effects could be dangerous.
(v) D.D.T is not metabolized very rapidly by animals rather it gets deposited and stored in fatty tissues. Because of its dangerous effects, its use has been banned in U.S.A in 1973. However, in spite of its dangerous effects, D.D.T is still being used in India because of non-availability of other cheaper insecticides.
(b) Mukesh's suggestion is very important to protect our environment. Because of long-term dangerous side effects of D.D.T., it should not be used to save our environment.
