Topper Package chemistry-XII Unit ALKYL HALIDES

Topper Package chemistry-XII Permutation and CombinationsAlkyl Halides & Aryl Halides

50

MULTIPLE CHOICE QUESTIONSTOPIC (1) PREPARATION OF ALKYLHALIDE & PHYSICAL PROPERTIES

1. The boiling points of alkyl halides and theirparent hydrocarbons (RH) are in the order(a) RH > RI > RBr > RCl > RF(b) RI > RBr > RCl > RF > RH(c) RH > RF > RI > RBr > RCl(d) none of these

2. How many trichloro ethanes would be producedwhen 1, 1-dichloroethane reacts with chlorine(a) 1 (b) 2(c) 3 (d) 4

3. Best yield of alkyl halide R X is formed in2 2 2RCO Ag X RX CO AgX when 2X is:

(a) 2Cl (b) 2Br(c) 2I (d) 2F

4. Iodoform can be prepared from all except:(a) ethyl methyl ketone(b) isopropyl alcohol(c) 3-methyl-2-butanone(d) isobutyl alcohol

5. Which branched chain isomer of the hydrocar-bon with molecular mass 72u gives only one iso-mer of mono substituted alkyl halide?(a) Tertiary butyl chloride(b) Neopentane(c) Isohexane(d) Neohexane

6. The reaction conditions leading to the best yieldsof C2H5Cl are:(a) C2H6 (excess) + Cl2 UVlight

(b) C2H6 + Cl2 dark

roomtemperature

(c) C2H6 + Cl2 (excess) UVlight

(d) C2H6 + Cl2 UVlight

7.

(a) (b)

(c) (d)

8. Which of the following is added to chloroform ina small quantity before it is bottled for sale?(a) CH3OH (b) C2H5Cl(c) C2H5OH (d) AgNO3

TOPIC (2) CHEMICAL PROPERTIES9. The structure of the major product formed in the

following reaction is Cl

I

NaCNDMF

(a)CN

CN(b)

Cl

INC

(c)Cl

CN(d)

CN

I

10. A mixture of 1-chloropropane and 2-chloropropane when treated with alcoholic KOH,gives(a) prop-1-ene (b) prop-2-ene(c) isopropylene (d) both a & b

11. Identify C in the series,

alc. KOH NBS alc. KC N3 7C H I A B C

(a) 3 2( )CH CH CN (b) 2 2CH CH CH CN

(c) Br CH CH CN (d) 2CH CH CHCN|Br

12. The organic chloro compound, which showscomplete stereochemical inversion during a

2NS reaction, is(a) 3 2( )CH CHCl (b) 3CH Cl(c) 2 5 2( )C H CHCl (d) 3 3( )CH CCl

13. Vicinal and gem dihalides can be distinguishedby(a) aqueous KOH (b) alcoholic KOH(c) Zn dust (d) none of these

14. 3AgNO does not give precipitate withchloroform because(a) 3CHCl is insoluble in water(b) 3CHCl does not ionise in water

Unit6

ALKYL HALIDES &ARYL HALIDES


51

(c) 3CHCl is an organic compound(d) 3AgNO is insoluble in 3CHCl

15. The final product formed by distilling ethylalcohol with excess of Cl2 and Ca OH 2( ) is(a) CH CHO3 (b) CCl CHO3(c) CHCl3 (d) CH O3 2( )

16. The end product (B) in the following sequence of

reactions is H O HKCNCH Cl A B2 /3

(a) CH COOH3 (b) HCOOH

(c) CH NH3 2 (d) CH COCH3 3

17. Which one of the following is most reactivetowards nucleophilic substitution reaction?

(a) CH CH Cl2 (b) C H Cl6 5

(c) CH CH CH Cl3 (d) ClCH CH CH2 2 .

18. In 1SN (substitution, nucleophilic, unimolecular)reaction, the racemization takes place, it is dueto(a) inversion of configuration(b) retention of configuration(c) conversion of configuration(d) both A and B.

19. Grignard reagent is not prepared in aqueousmedium but prepared in ether medium, because(a) the reagent is highly reactive in ether(b) the reagent does not react with water(c) the reagent becomes inactive in water(d) the reagent reacts with water.

20. Tertiary alkyl halides are practically inert tosubstitution by 2SN mechanism because of(a) insolubility (b) instability(c) inductive effect (d) steric hindrance

21. In which of the following reactions, the productis an ether?(a) C H CH COCl6 6 3 / anhydrous AlCl3(b) C H Cl2 5 + aq. KOH

(c) C H C H COCl6 6 6 5 /anhydrous AlCl3(d) C H Cl C H ONa2 5 2 5

22. Phosgene is a common name of(a) mixture of CO2 and Cl2(b) POC 3l(c) carbonyl chloride(d) carbon tetrachloride.

23. Arrange the following halides in the decreasingorder of

NS 1 reactivity

(I) CH CH CH Cl3 2 2 (II) CH CHCH Cl CH2 3( )

(III) CH CH CH Cl CH3 2 3( )(a) I > II > III (b) II > I > III(c) II > III > I (d) III > II > I

24. End product of following sequence of reaction is:

Br 3 23 /O H ONH BaOA B C

(a) O (b) OH

(c) O (d)HOOC COOH

25. In the following reaction final product is

Br

NaIacetone

X

(a)

I

X

(b) I

X

(c) both (a) and (b) (d) none of these26. How many chiral compound are possible on

monochlorination of 2-methyl butane?(a) 2 (b) 4(c) 6 (d) 8

27. Which of the following is the major product ofthe following reaction?

(a)

(b)


52

(c)

(d)

28. CH3 – Br + Nu– CH3 – Nu + Br–

The decreasing order of the rate of the abovereaction with nucleophiles (Nu–) A to D is:[Nu– = (A) PhO–, (B) AcO–, (C) HO–, (D) CH3O](a) D > C > A > B (b) D > C > B > A(c) A > B > C > D (d) B > D > C > A

29. In Finkelstein Reaction, which reactants areused(a) NaI + C2H5OH (b) NaF + acetone(c) NaBr + CH3OH (d) NaI + acetone

30. Racemic mixture is obtained due to the haloge-nation of(a) isopentane (b) n-pentane(c) neopentane (d) both (1) and (2)

31. The reaction of SOCl2 on alkanols to form alkylchlorides gives good yields because(a) alkyl chlorides are immiscible with SOCl2

(b) the reaction does not occur via intermediateformation of an alkyl chlorosulphate

(c) alcohol and SOCl2 are soluble in water(d) the other products of the reaction are gas-

eous and escape out

32. For CH3Br + OH– CH3OH + Br– the rate ofreaction is given by the expression(a) rate = k[CH3Br](b) rate = k [OH–](c) rate = k [CH3Br] [OH–](c) rate = k[CH3Br]0 [OH–]0

33. Consider the following reactions, which are car-ried out at the same temperature.

EtOH3 3CH Br OH CH OH Br .......(i)

DMSO3 3CH Br OH CH OH Br .......(ii)

Which of the following statement is correct aboutthese reactions.(a) Both the reactions take place at the same

rate(b) The first reaction takes place faster than

second reaction(c) The second reaction takes place faster than

first reaction(d) Both the reactions take place by SN1 mecha-

nism

34. Which of the following is the example of SN2 re-action?(a)

(b)

(c)(d)

35. Which of the correct reaction coordinate diagramfor the following solvolysis reaction?

(a) (b)

(c) (d)

36. CH – CH – C (Br) CH 3 3

H3C CH3

MeO K– +

X Major

Y MajorEt COK3

X and Y are respectively:

(a)CH3

CH3

C CCH3

CH3and C C

H

H(C ) CH2H3

CH3

(b) CH3

CH3

C C

CH3

CH3andC C

H

H(C ) CH2H3

CH3

(c)CH3

CH3

C C

CH3

CH3and C C

C H2 5 CH3

C H2 5 C H2 5

(d)H

HC C

CH3

(CH3)3and C C

CH3 CH3

CH3CH3


53

37. The dehydrobromination of 2-bromobutane givesCH3CH = CHCH3. The product is:(a) Hoffmann product(b) Saytzeff product(c) Hoffmann-Saytzeff product(d) Markownikoff product

38. alc.KOHBr

A

A may be:(a) (b)

(c) (d) All of these

39.

Br

CHCH3 CH CH3

CHO

CCH3

OHCC

H

CH3

Path of the reaction mechanism:(a) E1 (b) E2

(c) E1CB (d) both E1 & E2

40. Consider the following sequence of reaction.2 3 2

3

NaNH (excess) CH CH Br3 2

NH (I)CH CHBrCH Br (A) (B)

The two products (A) and (B) are respectively

(a) 3CH C CH and 3 2 3CH CH C CCH

(b) 3CH C CNa and 3 2(CH ) CHC CH

(c) 3CH C CNa and 3 2 3CH CH C CCH

(d) 3CH C CH and 3 2 3CH CH CH CHCH41. A compound (X), C4H8Cl2, on hydrolysis with aque-

ous KOH gives a product (Y) which on heatingwith I2 and dilute NaOH gives a yellow precipi-tate of iodoform. The compound (X) is expectedto be:(a) CH3CH2CH2CHCl2(b) CH3CH2CCl2CH3

(c) CH3CH2CHClCH2Cl(d) ClCH2CH2CH2CH2Cl

Y = Br2/CHCl3

42. HBr H

F+ NaI (1 mole) 2Acetone

SN Major(A) ;

Major product of this reaction is:

(a) HI H

F (b) IH H

F

(c) H

Br HI (d) H

Br IH

43. Rank the following in order of decreasing rate ofsolvolysis with aqueous ethanol (fastest slow-est)

(1) H C2 C Br

CH3(2)

CH3

Br

(3) C CHCH CH(CH )2 23

Br

CH3

(a) 2 > 1 > 3 (b) 1 > 2 > 3(c) 2 > 3 > 1 (d) 1 > 3 > 2

44. Arrange the following three chlorides in decreas-ing order towards SN1 reactivity.

(1) Cl (2)Cl

(3)Cl

(a) 1 > 2 > 3 (b) 2 > 3 > 1(c) 2 > 1 > 3 (d) 3 > 2 > 1

45. Which of the following alkyl halide undergorearrangement in SN1 reaction?

(a) C CH

CH3

CH3CH3

CH3 I(b)

Cl

CH3

(c)

l

(d) All of these

46. Which of the following reactant will not favournucleophilic substitution reaction?

(a)Br

(b) Ph – Br

(c) C CH2

CH3

BrCH3

CH3

(d) All the above

47. Among the pairs, in which pair first compoundreacts faster then second compound in SN1 re-action?(a) CH3– CH2– CH2 – CH2 – Br or

CH2CH3

BrCH CH3

(b) CCH3

BrCH2 CH3

CH3

or CHCH3

BrCH CH3

CH3


54

(c)

HBr 3NaOCH

HOCH3

(d) Both (a) and (b)

51.CH C2–– lO

3 a

3 N

CH ONCH OH(S 1) Product

Which of the following products can be obtainedfrom above reaction?

(a)CH CH2–– O 3

O

(b) OCH3O

(c)O

OCH3

CH3

(d) All of these52. What is the principal product of the following re-

action?CH3

CH3

Cl

H

BrH

H

H + NaN3 Product

(a)

CH3

CH3

Cl

H

N3H

H

H (b)

CH3

CH3

H

H

HN3

H

Cl

(c)

CH3

CH3

Cl

H

HN3

H

H (d)

CH3

CH3

H

H

N3H

H

Cl

(c)

Br

or

Br

(d) CCH3

BrCH3

CH3

or CCH3

ICH3

CH3

48.

log

(rat

e)

CH – X3 Me– CH X2– Me CH – X2 Me C – X3

A SN²

SN1

B

Which of the following is true about given graphsA and B?

(a) A 1NS 2N

B S (b) A 2NS , 1N

B S

(c) 1A & B E (d) 2A & B E

49. In each of the following groups, which is thestrongest (best) nucleophile?

(I) (1) H3C – O– (2) O–

(3) H3 C – S– in CH3OH

(II) (1) OH– (2) H2O (3) NH –2 in DMF

(III) (1) O– (2) O– (3) CH3O– in DMSO

(a) I,3; II,3; III, 2 (b) I,1; II,1; III, 3(c)I, 1; II, 2;, III, 1 (d) I,3; II, 1; III, 3

50. Which of the following reaction is an elimina-tion reaction?

(a)

HOH 2 4H SO + H

(b)

H

Br

H

BrKI + IBr + KBr


55

(a) A reacts faster than B(b) B reacts faster than A(c) Both A and B reacts at the same rate(d) Neither A nor B reacts

58. Most reactive compound toward SN1

(a)

CH2 I

(b)

CH2 I

(b)

CH2 I

(d)

CH2 I

59.

C

CH

OH

23 2

32 4

1.NaNH (2eq.)__2.CH CH I

__3.CH I__4.H /Pd BaSO

Product (X) is:

(a)

CH CH2 3

CH 2 O CH3

(b)

OCH3

CH CH2 3

(c)

CH OCH CH2 2 3

CH3

(d)

O CH CH2 3

CH3

53. Which of the following is most reactive towardSN2 reaction?(a) CH2 = CH – CH2 – Cl(b) Ph – CH2 – Cl

(c) Me – O Cl(d)

O

Ph – C – CH – Cl2

54. 4-chloro-1-butanol + NaOH (B)Product (B) of the above reaction is:

(a)O

(b)O

(c)O

CH3

(d)

CH H2 3–C

O

55. Energy profile diagram for an exothermic reac-tion, 1 2 3A B C D , is given below:

The slowest rate of step of the reaction is:

(a) A B (b) B C

(c) C D (d) cannot predict

56. Me2C = CH – CH2 – CH2 – Cl 2

3

H OCaCO (X); Major

product of the reaction is:

(a) Me CMe

CH2 CH2 CH2

OH

(b) Me2C = CH – CH2 – CH2 – OH(c) Me C2 CH

OHCH CH2 OH

(d) CMe2

OH

57. Which of the following statements is correct re-garding the rate of hydrolysis of the compounds(A) and (B) by SN1 reaction ?

A

Br O

B

Br


56

60. The major product of the following reaction:

H

OH

HBr [ ]x

(a)

Br

H(b)

H

(c) HBr

(d) OHHTOPIC (3) PREPARATION & PHYSICAL

PROPERTIES OF ARYL HALIDE61. Chlorobenzene is

(a) less reactive than benzyl chloride(b) more reactive than ethyl bromide(c) nearly as reactive as methyl chloride(d) more reactive than isopropyl chloride

62. Westron is(a) vinyl chloride(b) allyl chloride(c) dichloroacetaldehyde(d) acetylene tetrachloride

63. Cl Heat Fe Br Zn HClC H A B C2 23 , / /7 8

Here, the compound C is(a) 3-Bromo, 2,4, 6-trichlorotoluene(b) o-bromotoluene(c) p-bromotoluene(d) m-bromotoluene

64. A solution of (+)-2chloro-2-phenylethane intoluene racemises slowly in the presence ofsmall amount of SbCl5 due to the formation of(a) Carbanion (b) Carbene(c) Free-radical (d) Carbocation

65.

CH2—CH3

O2NBr2. U.V. light

Br2/Fe(A)

(B)(A) & (B) are respectively

(a)

CH2CH3

O2NBr

and

CH2CH3

O2NBr

(b)

CH2CH3

O2NBr

and CH—CH3

O2N

Br

(c)

C2H5

O2NBr

and CH—CH3

O2N

Br

(d)CH—CH3

O2N

Br

and

CH2CH3

O2NBr

66. Consider the two reaction

(I)

(C6H )6

BrH

+ Br2FeBr3

(II)

D

D

DD

D

D

+ Br2FeBr3

(C D )6 6

Br

D

DD

D

D

Which is the correct statement ?(a) The rate of bromination is same in both the

cases(b) The rate of bromination in (I) is more than

in (II)(c) The rate of bromination in (II) is more than

in (I)(d) The rate of bromination in (I) is double than

in (II)

67. The compound ‘X’ in the following reaction is:

(a) (b)

(c) (d)


57

68. Toluene reacts with excess of Cl2 in presence ofsunlight to give a product which on hydrolysisfollowed by reaction with NaOH gives

(a)

COOH

Cl(b)

COOH

(c)

COONa

Na

(d) None of these

TOPIC (4) CHEMICAL PROPERTIES69. Aryl halides and Alkyl halides are distinguished

by(a) Alcoholic 3AgNO (b) Aq. 3AgNO(c) 3AgNO /ether (d) 3 3/AgNO NH

70. Silver benzoate will react with bromine inacetone to form

(a)

(b)

Br

(c)

COOAg

Br

(d)

O||C Br

71. The reaction of toluene with chlorine in thepresence of 3FeCl gives mainly(a) m-chlorobenzene(b) o- and p-chlor toluene(c) benzyl chloride(d) Benzoyl chloride

72. Which chloroderivative of benzene among thefollowing would undergo hydrolysis most readilywith aqueous sodium hydroxide to furnish thecorresponding hydroxyderivative?

(a)ClO N2

NO2

NO2

(b) ClO N2

(c) ClMe2N (d) C H6 5Cl

73. Which represents nucleophil ic aromaticsubstitution reaction?

(a) reaction of benzene with Cl2 in sunlight(b) benzyl bromide hydrolysis with water(c) reaction of NaOH with dinitrofluoro benzene(d) sulphonation of benzene.

74. Chlorination of toluene in presence of light andheat followed by treatment with aqueous NaOHand acidification gives(a) o-Cresol(b) p-Cresol(c) 2,4-Dihydroxytoluene(d) benzoic acid

75. The major product obtained when Br Fe2 / is

treated with HN

CH3

O

H C3 is

(a)

HNCH3

O

H C3

Br

(b)

HNCH3

O

H C3

Br

(c)

HNCH3

O

H C3

Br

(d)

HNCH3

O

H C3

Br

76. The decreasing order of reactivity towards OH

ions is(I) m-nitrobromobenzene(II) 2,4,6-trinitrobromobenzene(III) p-nitrobromobenzene(IV) 2,4-dinitro bromobenzene(a) I > II > III > IV (b) II > IV > III > I(c) IV > II > III > I (d) II > IV > I > III


58

77. o-Toluic acid on reaction with Br Fe2 gives

(a)

ClCO H2

(b)Br

CO H2

CH3

(c)

Br

CO H2

CH3

(d)Br

CO H2

CH3

78. In the reaction of p-chlorotoluene with KNH2 in

liq. NH3 , the major product is

(a) o-toluidine (b) m-toluidine(c) p-toluidine (d) p-chloroaniline

79. Which is not the Wurtz-Fittig reaction?

(a) CH2Cl + CH3Cl /Na ether

(b) CH2C +l Cl /Na ether

(c) Cl +CH C3 l /Na ether

(d) None of these

80.

H C3 CH3

Cl

CH3

FeCl3CH3NO , 0°C2

A ;

A is

(a)

CH3

CH3

CH3

(b)

CH2CH3

CH3H C3

(c) both are correct(d) none is correct

81. Cl

Cl

C

H

CCl3

The above structural formula refers to :(a) BHC (b) DNA(c) DDT (d) RNA

82. Which of the following is most reactive towardsSN2 reaction ?

(a)

CH3

Cl

(b)

Cl

(c)

Cl

Cl

(d)

NO2

Cl

83. (CH ) – CH – Cl22S

O

O4

2NaNHdimethoxy ethane (A);Product(A) is:

(a) (CH ) –CH CH2 3 2S

O

O

(b) S

O

O

(c) (CH ) –CH NH2 4 2 2S

O

O(d) None of these


59

84.

CH3

NBS

Major(A) Major product is (A) is:

(a)

Br

(b)

Br

(c)

Br

(d)Br

85.

CH3

Br2 2SO Cl NBS KSHhv (A) (B) (C) ,

Product (C) is:

(a)

SH

Br (b)

SH

Cl

(c)

Br

SH (d)

Br

86. C

CH3

C14 CH3CH3

H

OTs

Major product of the

reaction is:

(a)CH3

CH3

C14

CPh

CH3

(b) HC3 CCH3

CH

Ph

CH2

14

(c)CH3

CH3

C14C

Ph

CH3

(d)

CH3

CH3

C

14

CPh

CH3

87.Br

H H

CH3

+ OH– 2SNA; The product A

is:

(a)HO

H H

CH3

(b)HO

H

H

CH3

(c) Both (a) and (b) are correct(d) None is correct

88.

OH

CH OH2

HBrΔ (A),

OH

OCH3

HBrΔ (B)

Product (A) and (B) respectively are:

(a)

OH

CH Br2

and

OH

Br

(b)

OH

CH Br2

and

OH

OH

(c)

OHHO

CH3

and

Br

OCH3

(d)

Br

CH OH2

and

Br

OCH3


60

INTEGER TYPE QUESTION

1 . CH C C CH3 3

Br Br

Br Br

(a) NaNH2

(b) CH I3

CH C C C C CH3 3

a and b mole consumed.Value of a + b =

2 . a.

Br

alc. KOH (A) products

b.

Br

alc. KOH (B)

c. Br

alc. KOH (C)

d.

CH3

CH3

BrBr

H

alc. KOH (D)

Sum of A + B + C + D =3.

a.

OH

H

(A)

b. OH

H

(B)

c.

OH

H

(C)

d . OH

H

(D)

Total number of product obtained in above re-actions including minor product is (includ-ing stereoisomer)

4 .

Cl

ClCl

Cl

(a ) alC.KOH

Moles of alc. KOH consumed are:

5 .

CH OH2

OH (A) HBr ; Value of (A)

is:

6 . Ph CH CH 2

Br

Br

(X) NaNH2

Ph C C Na+–

(X = No. of moles of NaNH2)

7 .O

a PCl5 b NaNH2

CH I3

C C CH3

Cl

Sum of a + b =

8 .

Cl

CH3

CH OH3 ?

X = Total number of substitution and elimi-nation product (s). Find the value of X.

9 . 1, 2-Dibromopropane on treatment with Xmoles of NaNH2 followed by treatment withC2H5Br gives a pentyne. The value of X is :


61

ANSWER’SUNIT : 7. ALKYL, ARYL & HALIDE

1. b 2. b 3. b 4. d 5. b6. a 7. b 8. c 9. d 10. a11. b 12. b 13. a 14. b 15. c16. a 17. d 18. d 19. d 20. d21. d 22. c 23. c 24. c 25. b26. b 27. b 28. a 29. d 30. d31. d 32. c 33. c 34. d 35. a36. a 37. b 38. d 39. c 40. c41. b 42. b 43. c 44. b 45. d46. d 47. b 48. b 49. d 50. d51. d 52. c 53. d 54. b 55. a56. d 57. b 58. d 59. b 60. c61. a 62. d 63. d 64. d 65. b66. a 67. b 68. b 69. a 70. b71. b 72. a 73. c 74. d 75. a76. b 77. c 78. b 79. a 80. b81. c 82. d 83. b 84. a 85. b86. c 87. b 88. b

INTEGER QUESTIONS1. 8 2. 8 3. 9 4. 2 5. 16. 3 7. 5 8. 4 9. 3

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Topper Package chemistry-XII Unit ALKYL HALIDES