CHAPTER 1

ORGANIC CHEMISTRY

PART A (MULTIPLE CHOICE)

1. A 15. C 29. D2. 4-ethyl-2,2-dimethylhexane 16. B 30. A3. B 17. A 31. C4. A 18. B 32. B5. B 19. D 33. A6. C 20. A 34. D7. C 21. B 35. A8. C 22. B 36. D9. A 23. A 37. C10. B 24. D 38. B11. D 25. C 39. B12. C 26. B 40. D13. A 27. A 41. A14. B 28. A

PART B (STRUCTURED QUESTION)

Alkane, Alkene, Alkyne

1. i) butane (C4H10), butene (C4H8), butyne (C4H6) ii) nonane (C9H20), nonene (C9H18), nonyne (C9H16) iii) hexane (C6H14), hexane (C6H12), hexyne (C6H10)

2. i) propane (C3H8), propene (C3H6), propyne (C3H4) ii) pentane (C5H12), pentene (C5H10), pentyne (C5H8) iii) heptane (C7H16), heptane (C7H14), heptyne (C7H12)

3. i) CnH2n ii) CnH2n iii) CnH2n-2 iv) CnH2n-2

4. i) CnH2n ii) CnH2n+2 iii) CnH2n-2 iv) CnH2n-2

5. a) 5-ethyl-2-methylheptane b) 3,3-dimethylbutyne

6 a) 1,1-dichloro-3,3-dimethylbutene b) 5-ethyl-2-methylheptane

7 a)

heptyne

b)

cis-3-octene

c)

Br

1-bromo-3-methylcyclohexene

d)

1-isopropenyl-2-methylcyclopropane

8 a)

heptene

b)

6-isopropyl-2,3-dimethylnonane

c)

cyclobutylcyclopentane

d)

1-t-butyl-2-methylcyclopropane

9. Initiation

Cl2 Cl + ClPropagation

CH4 + Cl CH3 +

HCl

CH3 + Cl2 CH3Cl + Cl

Termination

CH3 + Cl CH3Cl

10. Cl Cl Cl + Cl

H HH H

H C C H + Cl H C C + HCl

H HH H

H H H H

H C C + Cl Cl CH C Cl + Cl

H H H H

H H H

+H C C Cl

Cl H C C Cl + HCl

H H H H

H H Cl

H C C Cl + Cl Cl H C C Cl + Cl

H H H H

11. a)

b)

c)

d)

12. a)

b)

c)

d)

13. a)

b)

c)

d)

Ni

1-Hexyne + 2H2 Hexane

1-HexyneNi hv

Hexane +

2Cl2+2H2 o 1,1-dichlorohexane60 C

1-Hexyne +2H2Ni +

Br heat 1-bromohexaneHexane2

Ni

1-Hexyne + H2 1-Hexene

Ni

3-Hexyne + 2H2 Hexane

Ni hv3-Hexyne +2H2 2Cl2 3,3-dichorohexaneHexane +

60oC

3-Hexyne +2HNi

I2 heat 3-iodohexaneHexane+2

Ni

3-Hexyne + H2 3-Hexene

H H H H H H

H C C C C C C H

H H H H H H

H H H H H H

H C C C C C C

H H H H H

H H H H H H

H C C C C C C H

H H H H OH OH

H H H H OH

+ COOHH C C C C C

H H H H O

H H H H H H

e)

H C C C C C C OH

f)

H H H H H

H H H H H

HC

C C C C C Cl

H H H H H

g) H H H H H Cl

H C C C C C C Cl

H H H H H H

H H H H Cl H

h)

H C C C C C C

H H H H Cl

i) H H H H Cl H

H C C C C C C Cl

H H H H Cl Cl

14. a) H H H H H H H

H C C C C C C C H

H H H H H H H

b)

H H H H H H

H C C C C C C C H

H H H H H H

c)H H H H OH H H

H CC

C C C C C H

H H H OH H H Hd)

H H H OH O H H

H C C C C + C C C H

H H H O OH H H

e)

f)

g)

h)

i)

15. a.

H H H H OHH H

H C C C C C C C H

H H H H H H H

H H H H Cl H H

H C C C C C C C H

H H H H H

H H H H Cl H H

H C C C C C C C H

H H H H Cl H H

H H H Cl H H

H C C C C C C C H

H H H Cl H H

H H H Cl Cl H H

H C C C C C C C H

H H H Cl Cl H H

Name of reaction : Addition reaction

b. CH3CH2CH2CH(OH)CH3

16. a. KOH/ethanol

b. Step 1: Mg/ether

Step 2: H2O/H+

17. H H H CH3 H H H H CH3 H

H + H+H C C C C C H C C C C C H

H H H H H H H

+ Br -

H H H CH3 H

H C C C C C H

H H H Br H

18.H H H CH3 H H H H CH3 H

C H +Br-Br

H C C C C H C C C C C H

BrH H H H H H

+ Br-

H H H CH3 H

H C C C C C H

H H Br Br H

19.

Alcohols

20 a) ethanol

b) 2-methyl-2-propanol

c) 2-ethyl-1-butanol

21 a) 2-propyl-1-hexanol

b) 2,2-dimethyl-1-propanol

c) methanol

OH22 a)

b)

OH

c)

OH

Cl

23 a) OH

b) Br OH

c)OH

24 CH3CH2OH + K CH3CH2OK + ½ H2

Potassium ethoxide

25 CH3CH2CHOHCH3Excess H2SO4 CH3CH=CHCH3 + CH3CH2CH=CH2 + H2O∆

(major) (minor)

Rule: Saytzeff’s rule

26 a) CH3CH2CH2COOH

b) no product formed

27 a) CH3CH2CH2CH2OHKMnO4/

CH3CH2CH2CHO KMnO4/ CH3CH2CH2COOH+

H+/H /

b) CH3CH=CH2 HBr CH3CHBrCH3 OH-CH3CHOHCH3

c) CH3CH2OH HBr CH3CH2Br + H2O

d) CH3OH + CH3COOHconc.

CH3COOCH3 + H2OH2SO4

28

1-propanol 2-propanol

a) Oxidation a) Oxidation

1-propanol propanoic acid 2-propanol 2-propanone

b) Iodoform test b) Iodoform test

1-propanol X 2-propanol CHI3

c) Lucas test c) Lucas test

1-propanol X 2-propanol 2-chloropropane

29 Reagent X = concentrated H2SO4

IUPAC name = 1-butene or but-1-ene

H H

C C

CH2CH3H

30 (CH3)3COH

31 a)

H H OH H

H C C C C H

H H H H 2-butanol

b)

H H Br H H H

H C C C C C C OH

H H H H H H 4-bromo-1-hexanol

32 a) CH3CH2CH(CH3)CHO or CH3CH2CH(CH3)COOH

2-methyl-2-butanal 2-methylbutanoic acid

b) CH3CH2ONa + H2

Sodium ethoxide hydrogen

33 a) A = 2-methyl-1-propanol

b) B = 2,4-dimethyl-1-butanol or 3,3-dimethyl-2-butanol or 2,3-dimethyl-2-butanol

Alkyl Halide

34

H H Cl H H H H Cl H

H C C C H Cl C C C ClH C C C H

H H Cl H H H H Cl H

1,1-dichloropropane 1,3-dichloropropane 2,2-dichloropropane

H Cl H

H C C C H

Cl H H

1,2-dichloropropane

35 a) 3-bromopentane

b) 1-fluoropropane

c) 2-iodopropane

36 a)

I

b)

Br

c)

Cl

Cl

Cl

37 CH3CH2 H2OH HBr CH3CH2CH2Br + H2O

38 2-iodo-4-methylhexane

39 CH3CH2CHICH3

ethanolic KOHCH3CH=CHCH3 + CH3CH2CH=CH2 + HI

reflux (major) (minor)

Major: 2-butene, Minor: 1-butene

40 CH3CH=CH2 (1-propene)

41 CH3C(CH3)(Cl)CH3 or CH3C(CH3)(Br)CH3 or CH3C(CH3)(I)CH3

ether42 CH3CH2CH2Br + Mg CH3CH2CH2MgBr + H2O

CH3CH2CH3 + OH-Mg-Br

43 CH3CH2CH2Cl + OH - Reflux CH3CH2CH2OH∆

44 1-bromo-1-methylcyclohexane. Because in SN1, the reaction involved the carbocation

formation,therefore the tertiary carbocation is more stable compared to secondary

carbocation. So the 1-bromo-1-methylcyclohexane is more reactive than 1-bromocyclohexane in nucleophilic substitution in SN1.

45

SN1 SN2

RX Nu RX

46.

slow

H I

fast

O +

H H

H

fast

O

H H H

O H

O

47. Because to get the most stable carbocation .

48. HH

HO C I

H

49.H

+ O H

IO

50.H

H Cl Cl Cl

C C C C

H Cl andH

H

51.

Br2-bromo-6-ethyl-5-isopropyl-3-methyl-octane

52. Reagent Y = HBr

Aldehydes & Ketones

53. aldehyde, ketone, aldehyde/ketone, aldehyde, ketone

54. 3-methylbutanal

55. CH2(OH)(C≡N)

56. CH3CH(OH)(C≡N)

57. a)

O

O

b)

OH

O+ 2Ag+ + H2O

O+ 2Ag + 2H+

O

+ 2Ag+ + H2O no reaction

c) propanoic acid

58. a)

O

O

b)

OO

+ 2Ag+ + H2O OH

+ 2Ag + 2H+

O+ 2Ag+ + H2O no reaction

c) butanoic acid

59. a) sodium borohydride

b) HCHO + 2HNaBH4

CH3OH

c) Reduction

60. a) Lithium aluminium hydride

b) CH3CHO + 2H LiAlH4 CH3CH2OHether

61. Ketone: propanone; Reagent: KMnO4/H+, heated

62. CH3(CH2)6CH2OH KMnO4/H+ CH3(CH2)6CHO KMnO4/H+ CH3(CH2)6COOH∆ ∆

Octanoic acid

63. Tollen’s reagent

Tollen’s reagent is a mild oxidizing agent. When butanal is warmed with Tollen’s

reagent, it will be oxidized to butanoic acid while the silver mirror amine complex

[Ag(NH3)2]+ will be reduced to grayish Ag metal forming a silver mirror on the walls of the

test tube.

CH3CH2CH2CHO + 2Ag+ + H2O CH3CH2CH2COOH + 2Ag + 2H+

Butanone will not be oxidized by any oxidizing agent, including Tollen’s reagent.

64. W = 2,3,3-trimethylbutanoic acid

65. a)

O

b) Iodoform test

Reagents: iodine in aqueous sodium hydroxide

Observations: Pale yellow solid with a characteristic smell for compound having

CH3C O

group. No reaction for butanal.

Chemical equation:

CH3CHO + 3 I2 CI3CHO

CI3CHO + OH- CHI3 + HCOO-

66. a) Oxidation test with KMnO4 or K2Cr2O7

O O

KMnO4/H+

Heat OH

Purple colour of KMnO4 decolourised by aldehydes while ketones do

not. OR

Orange dichromate ion (Cr2O7-) is reduced to green colour by aldehydes while

ketones do not.

Tollen’s reagent: silver mirror test

O O

+ 2Ag+ + H2O OH + 2Ag + 2H

+

Colourless Tollen’s reagent is reduced to grey metallic silver by aldehydes while

ketones do not. Silver mirror on the wall of the test tube can be observed.

Fehling’s solution (a solution of cupric salt)

O O

+ 2Cu+ + 5OH

--+ Cu2O + 3H2O

O

Aldehydes reduce the deep blue colour of Fehling’s solution to brick-red (reddish

brown) precipitate of copper(II) oxide, while ketones do not.

b)

H H OH H

H C C C C H

H H H H 2-butanol

Carboxylic Acids

67 a) CH3CH2COOH

b) CH3CH(CH3)CH(OH)COOH

c) CH3(CH2)4COOH

d)

COOH

68 a) CH3COOH

b) CH3C(CH3)(Cl)COOH

c) CH3(CH2)8COOH

d) CH3(CH2)3COOH

69 CH3CH2CH2COOH + CH3OH

Butanoic acid

70 CH3COOCH2CH3 + NaOH

71 a) NaOH

b) CH3COOH

c) CH3CH2COOH

72 a) CH3COOH

b) CH3CH2CH=CHCH2OH

73 a) CH3CH2CH2COOH

b) CH2=CHCH2OH

74 a) ethyl ethanoate

b) methyl propanoate

c) sodium propanoate

conc. H2SO4

CH3CH2CH2COOCH3

refluxCH3COONa + CH3CH2OH

75 a) methyl butanoate

b) magnesium propanoate

c) sodium ethanoate

76 a) Methyl butanoate

conc. H2SO4b) CH3OH + CH3CH2CH2COOH CH3CH2CH2COOCH3 + H2O

Type of reaction: Esterification

77 a)

O

O

b) alcohol, carboxylic acid

Benzene & Aromatic Compounds (Introduction)

78 a)

Cl

b)

C2H5

c)

CH2Cl

d)

Br

F

79. a)

CH2OH

b)

CH2(CH2)5CH3

c)

NH2

d)

F

I

Amines

80. a) CH3NH2

b) CH2C(CH3)(NH2)CH3

c) (C2H5)2NH

d) CH3CH2CH2N(CH2CH3)(CH3)

81. secondary (N-methylethanamine),

tertiary (N,N-dimethylmethanamine),

primary (aniline),

secondary (N-ethylethanamine)

82. The formation of white precipitate after shaking.

83. a) CH3CH2NH2 + CH3CH2CH2Br → CH3CH2HNCH2CH2CH3 + HBr

[H+]b) CH3NH2 + CH3COCH2CH3 → CH3CCH2CH3 + H2O

║NCH3

CH3

│c) CH3N(CH3)2 → CH3NO

│CH3

84. a) CH3CH2CH2CH2NH2 b) CH3CH2CH

║NCH2CH3

+ +

85. CH3NH2 + CH3CHO → CH3CH → CH3CH2 ║ │

NCH3 NHCH3[H][H]