Haloalkanes and Haloarenes-Previous Years Questions

www.studyadda.com Haloalkanes And Haloarenes Previous Years’ Questions

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HALALKANES AND HALOARENES


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1 MARK QUESTIONS

1. Give the IUPAC name of the following compound.

[Delhi 2012]

2 2

3

CH C—CH Br|

CH

2. Write the IUPAC name of the following compound 3 3(CH ) 2CCH Br .

[Delhi 2011]

3. Write the IUPAC name of the following compound 2 2CH CHCH Br .

[All India 2011]

4. Write the structure of 1, 4-dibromobut-2-ene.

[Delhi 2011C]

5. Write the structure of 2-(2-bromophenyl) butane

[Delhi 2011C]

6. Write the structure of 2-(2- chlorophenyl )-1-isooctane.

[All India 2011C]

7. Write the structure of the following compound: 1-bromo-4-sec. butyl-2-methyl benzene.

[All India 2011C]

8. Which will react faster in

2S N displacement, 1-bromopentane or 2-bromopentane and why?

[Foreign 2011, 2010]

9. Write the IUPAC name of the following.

[All India 2010; Delhi 2008]


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10. A solution of KOH hydrolysis 3 2 3CH CHCICH CH and 3 2 2 2CH CH CH CH CI . Which one of these is more

easily hydrolyzed?

[Delhi 2010]

11. Give the IUPAC name of the following.

[All India 2010; Foreign 2009]

12. Write the structure of the compound 4- tert.butyl-3-iodoheptane.

[All India 2010C]

13. Write the IUPAC name of the following compound.

[All India 2010C]

14. Write the structure of the compound 1-chloro-4 ethylcyclohexane .

[All India 2010C]

15. Draw the structure of the following compound: 4-bromo-3-melhylpent-2-ene.

[Foreign 2010]

16. Write the structure of the following organic compound: 2-chloro-3-methylpentane.

[All India 2009C]

17. Write a chemical reaction in which the iodide ion replaces the diazonium group in a diazonium salt.

[Delhi 2008]


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18. Write the IUPAC name of 2 2ClCH C CCH Br

[All India 2008C]

19. Write IUPAC name of

[Foreign 2008]

20. Which one of the two compounds 3CH Br and 3CH l will react faster in an NS 2 reaction With

—OH? [Foreign 2007]

2 MARKS QUESTIONS

21. Explain as to why

(i) alkyl halides, though polar, are Immiscible with water?

(ii) Grignard's reagent should be prepared under anhydrous conditions?

[Foreign 2012]

22. What are ambient nucleophiles? Explain giving an example.

[Foreign 2012]

23. Which one in the following pairs of substances undergoes NS 2 substitution reaction faster and

why?

[Delhi 2009] (i)

(ii)


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24. Which one in the following pairs undergoes NS 1 substitution reaction faster and why?

[All India 2009]

(1)

(2)

25. Complete the following reaction equations.

(i)

(ii) 3 2 2CH CH CH CH HBr

[All India 2009]

26. Suggest a possible mechanism for the following reaction :

2,EtOH H On m BuBr KCN n BuCN

[Delhi 20090; All India 2008C]

27. Suggest a possible reason for the following observations.

[Delhi 2009C]

(i) The order of reactivity of haloalkanes is RI > RBr > RCI.

(ii) Neo- pentyl chloride, 3 3 3( )CH C CH CI does not follow NS 2 mechanism.

28. Complete the following reaction equation.

(i) 6 5 2C H N Cl KI

(ii)

[Delhi 2008; All India 2008]


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29. Discuss the mechanism of NS 1 reaction of haloalkanes.

[Delhi 2008C]

30. Give one example of

[Delhi 2007] (i) Wurtz reaction

(ii) Wurtz fitting reaction

31. What happens when iodoform is heated silver powder? Write chemical reaction.

[All India2007]

32. What type of reaction is known as nucleophilic substitution reaction? Give one example.

[Delhi 2006]

33. Write IUPAC name of the following compound.

[All India 2008]

(i)

(ii)

3 MARKS QUESTIONS

34. Although chlorine is an electron withdrawing group, yet it is ortho-para-directing in electrophilic aromatic substitution reactions. Explain, why is it so?

[Delhi 2012]

35. Answer the following questions.

(i) What is meant by chirality of a compound? Give an example.


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(ii) Which one of the following compound is more easily hydrolyzed by KOH and why? 3 2 3 3 2 2 2CH CHCICH CH orCH CH CH CH CI

(iii) Which one undergoes NS 2 substitution reaction faster and why?

or

[All India 2012]

36. Answer the following.

(i) Haloalkanes easily dissolve is organic solvents Why?

(ii) What is known as racemic mixture? Give an example.

(iii) Of the two bromo derivatives

6 5 3( )C H CH CH Br and 6 5 6 5( ) ( )C H CH C H Br which one is more reactive in NS 1 substitution

reaction and why?

[Delhi 2011]

37. Rearrange the compounds of each of the following sets in order of reactivity towards NS 2

displacement.

(i) 2-bromo-2-methyl butane, 1-bromopentane, 2- bromopentane.

(ii) 1-bromo-3-methyl butane, 2-bromo-2-methyl butane, 3-bromo-2-methyl butane.

(iii) 1-bromobutane, 1-bromo-2, 2-dimethyl propane, 1-bromo-2-methyl butane 1-bromo-3-methyl butane

[All India 2011]

38. (i) Write the mechanism of the following reaction.

n - 2,EtOH H On BuBr KCN n BuCN

(ii) Why is the dipole moment of chlorobenzene lower than that cyclohexyl chloride?

[Delhi 2011C]

39. (i) Write a chemical test to distinguish between

l Cl


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(a) chlorobenzene and benzyl chloride

(b) chloroform and carbon tetrachloride

(ii) Why is methyl chloride hydrolysed more easily than chlorobenzene?

[All India 2011C]

40. Complete die following reaction equations.

(i)

(ii)

(iii) 3 2 2CH +HBrCH CH CH

[Foreign 2011, 2009]

41. (i) State one use of DDT and iodoform. (ii) Which compound in the following? Couples will react faster in NS 2 displacement and why?

(a) 1-bromopentane or 2-bromopentane

(b) 1 – bromo-2-methylbutane or 2 bromo-2- methyl butane.

[Delhi 2010]

42. How would you differentiate between NS 1 and NS 2 mechanism of substitution reactions? Give one

example of each.

[All India 2010]

43. Explain why

(i) the dipole moment of chlorobenzene is lower than that of cydohexyl chloride?


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(ii) alkyl halides though polar are immiscible with water.

(iii) in the pair, 3 3( )CH —C— Cl and 2ClCH , 2ClCH will react faster in NS 2 reaction with —OH.

[All India 2010C]

44. Give reasons for the following observations.

(i) p-dichlorobenzene has higher melting point than those of o and m-isomers.

(ii) Haloarenes are less reactive than haloarenes towards nucleophilic substitution reaction.

(iii) The treatment of alkyl chloride with aqueous KOH leads to the formation of alcohol but in the presence of alcoholic = KOH, alkenes is the major product.

[All India 2009C Delhi 2008, 2008C]

Haloalkanes and Haloarenes-Previous Years Questions

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