Solutions of chapter 10. Haloalkanes and Haloarenes

1

The order of reactivity of following alcohols with halogen acids is ___________.

(A) CH₃CH₂ —CH₂—OH

(B)

(C)

2

Which of the following alcohols will yield the corresponding alkyl chloride on reaction with concentrated HCl at room temperature?

3

Identify the compound Y in the following reaction.

(i)

(ii)

(iii)

(iv)

4

Toluene reacts with a halogen in the presence of iron (III) chloride giving ortho and para halo compounds. The reaction is

5

Which of the following is halogen exchange reaction?

6

Which reagent will you use for the following reaction?

CH₃CH₂CH₂CH₃→ CH₃CH₂CH₂CH₂Cl + CH₃CH₂CHClCH₃

7

Arrange the following compounds in the increasing order of their densities.

(a)

(b)

(c)

(d)

8

Arrange the following compounds in increasing order of their boiling points.

(a)

(b) CH₃CH₂CH₂CH₂Br

(c)

9

In which of the following molecules carbon atom marked with asterisk (*) is asymmetric?

(a)

(b)

(c)

(d)

10

Which of the following structures is enantiomeric with the molecule (A) given below :

A.

B.

C.

D.

11

Which of the following is an example of vic-dihalide?

12

The position of –Br in the compound in CH₃CH==CH—C(Br)(CH₃)₂ can be classified as ____________.

13

Chlorobenzene is formed by reaction of chlorine with benzene in the presence of AlCl₃. Which of the following species attacks the benzene ring in this reaction?

14

Ethylidene chloride is a/an ______________.

15

What is ‘A’ in the following reaction?

A.

B.

C.

D.

16

A primary alkyl halide would prefer to undergo _____________.

17

Which of the following alkyl halides will undergo S_N1 reaction most readily?

18

Which is the correct IUPAC name for:

19

What should be the correct IUPAC name for diethylbromomethane?

20

The reaction of toluene with chlorine in the presence of iron and in the absence of light yields ____________.

A.

B.

C.

D. Mixture of (ii) and (iii)

21

Chloromethane on treatment with excess of ammonia yields mainly

22

Molecules whose mirror image is non superimposable over them are known as chiral. Which of the following molecules is chiral in nature?

23

Reaction of C₆H₅CH₂Br with aqueous sodium hydroxide follows ____________.

24

Which of the carbon atoms present in the molecule given below are asymmetric?

25 N

Which of the following compounds will give racemic mixture on nucleophilic substitution by OH^– ion?

(a)

(b)

(c)

26

(a)

(b)

(c)

27

(a)

(b)

(c)

28

(a)

(b)

(c)

29

(a)

(b)

(c)

30

Which is the correct increasing order of boiling points of the following compounds?

1-Iodobutane, 1-Bromobutane, 1-Chlorobutane, Butane

31

Which is the correct increasing order of boiling points of the following compounds?

1-Bromoethane, 1-Bromopropane, 1-Bromobutane, Bromobenzene

32

Which of the statements are correct about above reaction?

33

Which of the following statements are correct about this reaction?

34 Answer

Which of the following statements are correct about the reaction intermediate?

35

Which of the following statements are correct about the mechanism of this reaction?

36

Which of the following statements are correct about the kinetics of this reaction?

37

Haloalkanes contain halogen atom (s) attached to the sp3 hybridised carbon atom of an alkyl group. Identify haloalkane from the following compounds.

38

Ethylene dichloride and ethylidene chloride are isomers. Identify the correct statements.

39

Which of the following compounds are gem-dihalides?

40

Which of the following are secondary bromides?

41

Which of the following compounds can be classified as aryl halides?

42

Alkyl halides are prepared from alcohols by treating with

43

Alkyl fluorides are synthesised by heating an alkyl chloride/bromide in presence of ____________ or ____________.

44

Aryl chlorides and bromides can be easily prepared by electrophilic substitution of arenes with chlorine and bromine respectively in the presence of Lewis acid catalysts. But why does preparation of aryl iodides requires presence of an oxidising agent?

45

Out of o-and p-dibromobenzene which one has higher melting point and why?

46

Which of the compounds will react faster in S_N1 reaction with the ^–OH ion?

CH₃— CH₂— Cl or C₆H₅— CH₂— Cl

47

Why iodoform has appreciable antiseptic property?

48

Haloarenes are less reactive than haloalkanes and haloalkenes. Explain.

49

Discuss the role of Lewis acids in the preparation of aryl bromides and chlorides in the dark.

50

Which of the following compounds (a) and (b) will not react with a mixture of NaBr and H₂SO₄. Explain why?

(a) CH₃CH₂CH₂OH

(b)

51

Which of the products will be major product in the reaction given below?

Explain.

CH₃CH=CH₂ + HI → CH₃CH₂CH₂I + CH₃CHICH₃

(A) (B)

52

Why is the solubility of haloalkanes in water very low?

53

Draw other resonance structures related to the following structure and find out whether the functional group present in the molecule is ortho, para directing or meta directing.

54

Classify the following compounds as primary, secondary and tertiary halides.

(i) 1-Bromobut-2-ene

(ii) 4-Bromopent-2-ene

(iii) 2-Bromo-2-methylpropane

55

Compound ‘A’ with molecular formula C₄H₉Br is treated with aq. KOH solution. The rate of this reaction depends upon the concentration of the compound ‘A’ only. When another optically active isomer ‘B’ of this compound was treated with aq. KOH solution, the rate of reaction was found to be dependent on concentration of compound and KOH both.

(i) Write down the structural formula of both compounds ‘A’ and ‘B’.

(ii) Out of these two compounds, which one will be converted to the product with inverted configuration?

56

Write the structures and names of the compounds formed when compound ‘A’ with molecular formula, C₇H₈ is treated with Cl₂ in the presence of FeCl₃.

57

Identify the products A and B formed in the following reaction:

(a) CH₃—CH₂—CH=CH—CH₃+HCl → A + B

58

Which of the following compounds will have the highest melting point and why?

(I)

(II)

(III)

59

Write down the structure and IUPAC name for neo-pentylbromide.

60

A hydrocarbon of molecular mass 72 g mol^–1 gives a single monochloro derivative and two dichloro derivatives on photo chlorination. Give the structure of the hydrocarbon.

61

Name the alkene which will yield 1-chloro-1-methylcyclohexane by its reaction with HCl. Write the reactions involved.

62

Which of the following haloalkanes reacts with aqueous KOH most easily? Explain giving reason.

(i) 1-Bromobutane

(ii) 2-Bromobutane

(iii) 2-Bromo-2-methylpropane

(iv) 2-Chlorobutane

63

Why can aryl halides not be prepared by reaction of phenol with HCl in the presence of ZnCl₂?

64

Which of the following compounds would undergo S_N1 reaction faster and why?

(A)

(B)

65

Allyl chloride is hydrolysed more readily than n-propyl chloride. Why?

66

Why is it necessary to avoid even traces of moisture during the use of a Grignard reagent?

67

How do polar solvents help in the first step in S_N1 mechanism?

68

Write a test to detect the presence of double bond in a molecule.

69

Diphenyls are potential threat to the environment. How are these produced from arylhalides?

70

What are the IUPAC names of the insecticide DDT and benzenehexachloride? Why is their use banned in India and other countries?

71

Elimination reactions (especially b-elimination) are as common as the nucleophilic substitution reaction in case of alkyl halides. Specify the reagents used in both cases.

72

How will you obtain monobromobenzene from aniline?

73

Aryl halides are extremely less reactive towards nucleophilic substitution. Predict and explain the order of reactivity of the following compounds towards nucleophilic substitution from arylhalides?

(I)

(II)

(III)

74

tert-Butylbromide reacts with aq. NaOH by S_N1 mechanism while n-butylbromide reacts by S_N2 mechanism. Why?

75

Predict the major product formed when HCl is added to isobutylene. Explain the mechanism involved.

76

Discuss the nature of C–X bond in the haloarenes.

77

How can you obtain iodoethane from ethanol when no other iodine containing reagent except NaI is available in the laboratory?

78

Cyanide ion acts as an ambident nucleophile. From which end it acts as a stronger nucleophile in aqueous medium? Give reason for your answer.

79

Match the the compounds given in Column I with the effects given in Column II.

80

Match the items of Column I and Column II.

81

Match the structures of compounds given in Column I with the classes of compounds given in Column II.

82

Match the reactions given in Column I with the types of reactions given in Column II.

83

Match the structures given in Column I with the names in Column II.

84

Match the reactions given in Column I with the names given in Column II.