Match List-I with List-II
|
List-I |
List-II |
|
(A) Freons |
(I) Paint remover |
|
(B) DDT |
(II) Refrigeration |
|
(C) Dichloromethane |
(III) Fire extinguisher |
|
(D) Tetrachloromethane |
(IV) Insecticide |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(II), (B)-(IV), (C)-(I), (D)-(III)
Compounds with more than one halogen atom, the polyhalogen compounds, are widely used in industry and agriculture. Each use follows from a property of the compound: stability and easy liquefaction, toxicity to insects, or power as a solvent.
(A) Freons — This matches (II) Refrigeration. Freons are the chlorofluorocarbons of methane and ethane, such as freon-12, \( \ce{CCl2F2} \). They are stable, non-toxic, non-corrosive and easily liquefiable gases, so they are used in refrigeration, air conditioning and as aerosol propellants. Freon-12 is made from tetrachloromethane by the Swarts reaction:
\( \displaystyle \ce{3CCl4 + 2SbF3 -> 3CCl2F2 + 2SbCl3} \)
(B) DDT — This matches (IV) Insecticide. DDT (p,p′-dichlorodiphenyltrichloroethane) was the first chlorinated organic insecticide, used against the mosquitoes that spread malaria and the lice that carry typhus. Because it is not metabolised and is stored in fatty tissues, its use has been banned in many countries.
(C) Dichloromethane — This matches (I) Paint remover. \( \ce{CH2Cl2} \) is widely used as a solvent, as a paint remover, as a propellant in aerosols and as a metal cleaning solvent.
(D) Tetrachloromethane — This matches (III) Fire extinguisher. \( \ce{CCl4} \) is a dense, non-flammable liquid; until the mid-1960s it was widely used as a cleaning fluid and as a fire extinguisher. Today it is mainly a feedstock for chlorofluorocarbons.
Shortcut: (A)-(II) appears only in Option (3).