Give the uses of freon 12, DDT, carbon tetrachloride, and iodoform.
Uses of Freon−12
Freon-12(dichlorodifluoromethane,CF2Cl2)is commonly known as CFC. It is used as a refrigerant in refrigerators and air conditioners. It is also used in aerosol spray propellants such as body sprays, hair sprays, etc. However, it damages the ozone layer. Hence, its manufacture was banned in the United States and many other countries in 1994.
Uses of DDT
DDT(p,p−dichlorodiphenyltrichloroethane)is one of the best-known insecticides. It is very effective against mosquitoes and lice. However due to its harmful effects, it was banned in the United States in 1973.
Uses of carbontetrachloride(CCl4)
(i)It is used for manufacturing refrigerants and propellants for aerosol cans.
(ii)It is used as feedstock in the synthesis of chlorofluorocarbons and other chemicals.
(iii)It is used as a solvent in the manufacture of pharmaceutical products.
(iv) Until the mid-1960s, carbon tetrachloride was widely used as a cleaning fluid, a degreasing agent in industries,a spot reamer in homes, and a fire extinguisher.
Uses of iodoform(CHI3)
Iodoform was used earlier as an antiseptic, but now it has been replaced by other formulations containing iodine due to its objectionable smell. The antiseptic property of iodoform is only due to the liberation of free iodine when it comes in contact with the skin.
Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
(i) (CH3 )2CHNH2 (ii) CH3 (CH2 )2NH2 (iii) CH3NHCH(CH3 )2
(iv) (CH3 )3CNH2 (v) C6H5NHCH3 (vi) (CH3CH2 )2NCH3 (vii) m–BrC6H4NH2
Give one chemical test to distinguish between the following pairs of compounds.
(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylaniline
Account for the following:
(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv) Although amino group is o– and p– directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.
Give the IUPAC names of the following compounds:
(i)CH3CH(Cl)CH(Br)CH3
(ii)CHF2CBrClF
(iii)ClCH2C≡CCH2Br
(iv)(CCl3)3CCl
(v)CH3C(p-ClC6H4)2CH(Br)CH3
(vi)(CH3)3CCH=CClC6H4I-p
Write the structures of the following organic halogen compounds.
(i) 2-Chloro-3-methylpentane
(ii)p-Bromochlorobenzene
(iii)1-Chloro-4-ethylcyclohexane
(iv)2-(2-Chlorophenyl)-1-iodooctane
(v)2-Bromobutane
(vi)4-tert-Butyl-3-iodoheptane
(vii)1-Bromo-4-sec-butyl-2-methylbenzene
(viii)1,4-Dibromobut-2-ene
Which one of the following has the highest dipole moment?
(i)CH2Cl2
(ii)CHCl3
(iii)CCl4
A hydrocarbon C5H10 does not react with chlorine in the dark but gives a single monochloro compound C5H9Cl in bright sunlight. Identify the hydrocarbon.