INDIANSCHOOLAL WADI AL KABIR
DEPARTMENT OF SCIENCE 2015-2016
CHEMISTRY
CLASS : XII DATE: 12.04.15
W.S NO: 1 NAME:
TOPIC : HALOALKANES AND HALOARENES
1. Write the IUPAC nomenclature of the following compounds.
a. n-Butyl chloride b. Isobutyl chloride c. sec-Butyl bromide d. t-butyl chloride
e. Ethylidene chloride f. Ethylene dichloride g. m-ClC6H4CH2C(CH3)3 h. p-ClC6H4CH2CH(CH3)2
2. With the help of an example, discuss the stereochemistry involved in SN1 and SN2 mechanism.
3. Account for the following.
a. It is necessary to avoid even traces of moisture from Grignard reagent.
b. Chloroform is stored in dark coloured bottles.
c. Halogens are deactivating but o, p directing.
d. Presence of electron withdrawing group on benzene increases tendency of SN reactions.
e. Alkyl halides have higher boiling points than the corresponding hydrocarbons.
f. H3PO4 is used with KI for iodination of alcohols.
g. Benzylic and allylic halides follow SN1 mechanism.
h. Aryl halides do not undergo SN reactions easily.
i. CH3Cl when treated with KNO2 gives nitrite while AgNO2 gives nitro compounds.
4. . Define the following terms.
a. Optical activity b. Dextro and laevorotatory compounds c. Enantiomers
d. Racemisation e. Retention of configuration f. Chirality
5. Write short notes on
a. Sandmeyer reaction b. Wurtz-Fittig reaction c. Ambident species d. Fittig reaction
e. Swarts reaction f. Grignard reagent g. Finkelstein reaction h. Friedel Craft’s alkylation
6. Give the uses of a. CHCl3 b. CHI3 c. CCl4 d. Freon e DDT
7. Arrange the following in increasing order of property mentioned giving reasons.
a. Reactivity of 1°, 2° and 3° alkyl halides towards nucleophilic substitutions.
b. Dichlorobenzenes (melting points)
c. Ethanol and ethyl chloride (solubility in water)
d. Butyl bromides (boiling points)
8. What happens when
a. CHCl3 is exposed to air.
b. Cyclohexene is treated with Br2/ hν .
c. Methyl bromide is treated with metallic sodium in ether.
d. Chlorobenzene is treated with Mg in ether and then reacted with water.
9. Bring about the following conversions.
a. Propene to propan-1-ol b. Ethanol to butane
c. Benzene to 4-bromonitrobenzene d. 1- Bromopropane to 2- Bromopropane
e. Toluene to 4-bromotoluene f. Nitrobenzene to Iodobenzene
g. Ethane to Fluoroethane h. Benzyl alcohol to Phenyl ethanoic acid
i. Benzene to m-Nitroacetophenone
10. How will you distinguish between
a. CH3Cl and CH3Br b. Ethyl chloride and vinyl chloride
11. Identify the geminal and vicinal halides among the following.
a. cis- 1,2-dibromocyclopentane b. 3,3-Dichloropentane c. 1,3-Dibromoheptane
12. A hydrocarbon C5H10 does not react with Cl2 in dark but gives a single monochloridein bright sunlight.
Identify the hydrocarbon.
13. A chloro derivative (A) on treatment with Zn-Cu couple gives a hydrocarbon with five carbon atoms. When
(A) is dissolved in ether and treated with Na, 2,2,5,5-tetramethylhexane is formed. What is the formula of
the compound?
14.Although chlorine is an electron withdrawing group, yet it is ortho para directing in aromatic electrophilic
substitution.Why?
15. a. Identify chiral in CH3CHOHCH2CH3 and CH3CH(OH)CH3.
b. Among the following compounds, which one is more easily hydrolysed and why?
CH3CHClCH2CH3 or CH3CH2CH2CH2Cl
c. Which of these will react faster in SN2 displacement and why?
1-Bromopentane and 2-Bromopentane
16. Draw the structure of 4-Bromo-3-methylpent-2-ene.
17. Write a chemical reaction in which the iodide ion replaces the diazonium group in a diazonium salt.
18. Consider the three types of replacement of group X by group Y as shown here.
What is the process called if (a) A is the only compound formed ? (b) B is the only compound formed?
(c) A and B are formed in equal proportions?
19. Write the mechanism of the following reaction CH3CH2OH CH3CH2Br + H2O
20. Which product will be formed when optically active halide with formula C4H9Br is subjected to
dehydrohalogenation?
21. Write the structure of 2-(3-chlorophenyl)but-2-ene.
22. Give reason for the following.
a. The free radical bromination of n-butane yields 2-Bromobutane as the major product.
b. Allyl chloride is hydolysed much more easily than vinyl chloride.
Prepared by Mrs. Jasmin .J