ch: 10 haloalkanes & haloarenes – … · 7. while naming the compounds containing functional...

CLASS XI IUPAC RULES & PRACTICE SHEET

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IUPAC RULES

1. Longest Chain Rule:

• Select the longest continuous chain of carbon atoms as the parent chain.

• If some carbon-carbon multiple bond is present, the parent chain must include it.

• If two equally long chains are possible, the chain with maximum number of side

chains is selected as parent chain.

2. Lowest Number Rule: The number which indicates the position of the alkyl group in the

parent chain is also called locant. The numbering is done such that, the substituted carbon

atoms have lowest possible number.

3. Lowest Set of Locant Rule:

• If two or more different sets of locants containing same number of terms are

possible, then the two sets of locants (each one in order of increasing magnitude)

are compared term by term. The set of locants which contains the lowest number on

the occasion of first difference, is considered correct for numbering the carbon

atoms of parent chain.

Dear Students,

IUPAC nomenclature is the most important part of organic

chemistry. If you know nomenclature, organic chemistry

becomes very easy. So, check out the rules and then try to

the examples given in the following practice sheet. There are

as many as 149! examples given in the practice sheet. The

answers are given at the end of practice sheet.

Your journey to IUPAC nomenclature begins here!



• In case of unsaturated hydrocarbons, the carbon atom involved in the multiple

bond should get the lowest possible number.

4. Alphabetical arrangement of prefixes: If there are different alkyl substituents, their names

are written in alphabetical order. However, the numerical prefixes such as di, tri etc. are not

considered for the alphabetical order.

5. Naming of different alkyl substituents at equivalent positions: If two different alkyl

groups are located at equivalent positions, then numbering is done in such a way that, the

alkyl group alphabetically first gets the lower number.

6. Naming of the complex alkyl substituent:

• If the alkyl substituent is further branched, it is called substituted alkyl group.

• The carbon atoms of the alkyl group are separately numbered such that, the carbon

atom directly attached to the parent chain is given number 1.

• The prefix/name of such a substituent is enclosed in brackets.

• While writing the name of the substituted alkyl group, the first letter of the

complete name of the substituted alkyl group is considered.

• If same complex substituent occurs more than once, the prefixes such as bis (for

two), tris (for three), tetrakis (for four) & pentakis (for five) are used and are written

before the bracket starts.

• The name of the substituted alkyl group is enclosed in parenthesis.

7. While naming the compounds containing functional groups, it may be noted that..

• The terminal ‘e’ of the primary suffix is removed if the secondary suffix is followed

by ‘a’, ‘i’ , ‘o’ , ‘u’ or ‘y’.

• -NO2, -OR, -X (halo group) are considered as substituents and are indicated as

prefixes.

• Groups like –CHO, -CO-, -COOH, -COCl, -CONH2, -COOR, -CN & -OH are

considered as functional groups & are indicated by secondary suffix.

• The parent chain must include the carbon atom involved in the functional groups

like –COOH, -CHO etc. and their carbon atom must get the lowest number.

8. If the compound contains more than one functional similar functional groups, than in

addition to various rules, the numerical prefixes such as di (for two), tri (for three) are

added before the secondary suffix which indicates the functional group. While adding such

words, the vowel ‘e’ of the primary suffix is retained. Eg: Butane-1,2,3-triol.

9. If an unbranched carbon chain is linked directly to more than two carboxyl groups, these

groups are named by substitutive use of suffix ‘-tricarboxylic acid’ etc. The principal chain

should be linked directly to the maximum possible number of carboxyl groups. The

carboxyl groups which are not directly linked to the principal chain are expressed by

‘carboxyalkyl’ prefix. Eg: 3-(carboxymethyl)hexane-1,2,5-tricarboxylic acid. Similarly the

substitutive prefixes for aldehydes, cyanides, acylchlorides & amides are respectively

carbaldehyde, chlorocarbonyl, carbonitrile & carboxamide.



10. If the molecule contains more than one dissimilar functional groups, the parent chain must

contain maximum possible number of functional groups. The numbering of parent chain

should be done such that the functional group having higher priority gets the lowest

number.

11. Priority series: Carboxylic acids > acid anhydrides > esters > acid chlorides > amides >

nitriles, isocyanides > aldehydes > ketones > alcohols > amines > alkenes, alkynes > halo,

nitro, alkoxy, alkyl.

12. The functional group (according to the above priority series) which gets the lowest number

(higher priority) is indicated by the secondary suffix and the rest are considered as

substituents and are indicated by prefix. Eg: -OH by hydorxy, -CN by cyano, -NC by

isocyano, -CHO by formyl or oxo, -COOH by carboxy, -COOR by carbalkoxy, -COCl by

chloroformyl, -NH2 by amino, >CO by keto or oxo.

13. If two groups of same preference appear at identical positions from the either end of the

chain, then the groups whose prefix comes first in the alphabetical order gets the lower

number. Eg: 1-bromo-5-iodopentane.

14. If the compound is cyclic, the prefix ‘cyclo’ is used before the word root. The numbering is

done in such a way that the least possible number is assigned to the functional group or

substituent in accordance with the rules already discussed. Eg: 3-methylcyclohexanol, eg:

1-methyl-3-nitrocyclohexene, eg: 3-hydroxycyclohexanone.

15. Nomenclature of substituted benzene compounds:

• The carbon atoms of benzene are numbered from 1-6. The benzene ring is called the

nucleus and alkyl groups attached to the ring are called side chains.

• Benzene can form three di-substituted derivatives namely 1, 2 (ortho ‘o-’), 1, 4 (para

‘p-’), 1, 3 (meta ‘m-’).

• Tri & poly substituted derivatives are named by numbering the chain in such a way

that parent group gets the lowest number and the lowest locant rule is obeyed.

• C6H6 is benzene while C6H5- is phenyl group.



IUPAC PRACTICE SHEET

Write the IUPAC names of the following: (FIND ANSWERS AT THE END!)

1.

CH3

CH2 CH CH CH

CH2OHC

C2H5

2. CH3 CH CH2 OH

3.

CH3 CH2 CH C O CH3

C2H5 O

4. CH3 CH CH C OH

O

5.

CH3 CH C CH3

OCH3

6.

CH2 C C OC2H5

CH3

O

7.

CH3 CH CH CH2NH2

CH3

CH3

8.

CH3 C CH CH CH3

C2H5 CH3

O



9.

CH3 CH CH2 C Br

CH3

O

10.

CH3 C CH CH

CH2CH3CH3

CH3 CH3 I

11.

CH3

CH2 CH CH C CH3

Cl CH3

OH

CH3

12.

CH CHO

CH3

13.

CH3 C CH CH3

O

CH3

14.

CH3 CH2 CH CH C CH3

Cl CH3

OH

CH3

15.

CH3 C CH CH3

O

CH3

16.

CH3 C

CH3 C

O

O

O

17. CH2 CHO



18. CH3 CH CH2 Cl

CH3

19.

O C CH

O

CH3

CH3

20.

CH3 CH CH COOH

CH3

CH3

21.

CH3 C CH3

CHO

CH3

22.

C CH2 CH3

CH3

OH

23.

CH3 CH2 CH CONH2

CH3

24.

CH3 CH CH NH2

CH3

CH3

25.

CH3 CH2 CH COOC2H5

CH3

26.

CH3 CH C CH CH3

CH3

CH3O

27.

CH3 C CH2 C CH3

CH3

CH2CH3 CH2CH3

CH3



28.

C OH

CH3

CH3

CH3

29.

CH3 C C C CH2 CH3

O

30. CH3 CH2 CH CH

CHCHCH2CH3

31.

CH3 CH CH CH CH CH3

CH3

C2H5

32. CH3 CH CHO

OCH3

33. CH2 C COOCH3

CH3

34. OH CH COOH

OH CH COOH

35.

CH3 CH C COOH

CH3

O

36. NC CH2 CH2 COOH

37. CH2 COOH

C

CH2

OH COOH

COOH

38.

CH3 C CH CH2 C

COOC2H5

O

OH



39.

CH3 CH C C NH

CH3

O O

Br

40. CH2 C CH CH2OHCl

CH3

41.

CH2 CH C CH2 CH3Br

CONH2

O

42.

(H3C)3C CH2 CH2 Cl

43.

CH3 CH CH CH CHO

CH3

OH OH

44.

CH3 C CH CH2 CH2Cl

CH3

O

45.

CH3 CH CH2 C CH3

OH

O

46.

CH3 CH CH CH CH3

Cl

Br OH

47.

CH3 CH2 C CH CH2

Br

OH

Cl

Cl

48.

CH3 C CH CH2 CH2 Cl

O

C2H5



49. CH C CH2 CH2 CH CHO

Cl

50.

CH3 C C

O O

H

51.

CH3 CH C CH OCH3

CH3

CH3O

52. CH2 C CH2 CH2 OH

CH3

53.

CH CH C

O

OH

54.

CH3 CH C CH OCH2CH3

OCH3

O CH3

55. CH2 CH CH2

OH OHOH

56.

OH

O

OCH3

57.

OC

O

CH3

CH3



58.

CH3 CH2 CH C CH2Cl

Br Br

CH3

59. NH2

NO2

NO2

60.

CH C CHO

CH3

CH3

CH3

OCH3

61. CH3 CH COOH

CH2OHC

62.

CH3 C C OCH2CH3

O

O

63.

CH3 C C CH2 OCH3

O

O

64.

CH3 CH2 N C

Cl

H

O

65.

C OH

H

O

O

66.



67.

68. OH

69. OH

CH3

70. NO2

CH3

71. CH3

CH2CH3

72. CH CHCH3 CH2

73. O

OH

74. CH3

CH3

75.



76.

77.

78. OH

79.

80.

81. OH

O

82.

O

Br

83. CHO

CH3

84.

85. Me Me

MeMe

86. Et

87. COOH



88. OH

89. OH

CHO

90. CH3

CH3

O

91. Cl

Br

92. CHOCH3

93.

OH

94.

95.

Cl

O

96.

H3CO

O

97.

O OCH3



98.

99. Me

Me

OHH

HOH

100.

101. OH

H

HMe

102. Et

Me COOH

103.

O

O

104. N

105.

106.

CHO

107.

108.



109.

110.

111.

112. CH3

113. CH3

CH3

114. CH3

CH3

115. CH3

CH3

116. CH

CH2



117. CH3

CH3 CH3

118. CH3

Cl

119. Cl

Cl

120. CH2Cl

121. CH2 CH2 CH2 Cl

122. CH CH CH2 Cl

123. OH



124. OH

OH

125. OH

OH

126. OH

OH

127. CH2OH

128. CH2CH2OH

129. CHO

130. CH2CHO



131. COOH

132. COOH

OH

133. CH2COOH

134. CH2COOH

OH

135. COOH

COOH

136. COOH

COOH

137. COOH

COOH



138. COOH

OH

139. COOH

CH3

140. COCl

141. CONH2

142. CONH2

CONH2

143.

C

NH

C

O

O

144.

C O

O

C

O



145.

C

O

C

O

O

146. COOCH3

147. NH2

148. NH CH3

149. N CH3CH3

ANSWERS!!! 1. 5-ethylhept-3-enal

2. 2-phenylpropan-1-ol

3. methyl 2-ethylbutanoate

4. but-2-enoic acid

5. 2-methoxybut-2-ene

6. ethyl 2-methylprop-2-enoate

7. 2,3-dimethylbutan-1-amine

8. 3-ethyl-4-methylpentan-2-one

9. 3-methylbutanoyl bromide

10. 4-iodo-2,2,3-trimethylhexane

11. 4-chloro-2,3-dimethylhexan-2-ol

12. 2-phenylpropanal



13. 3-methylbutan-2-one

14. 4-chloro-2,3-dimethylhexan-2-ol

15. 3-methylbutan-2-one

16. Ethanoic anhydride

17. Phenylethanal

18. 1-chloro-2-methylprop ane

19. phenyl 2-methylpropanoate

20. 2,3-dimethylbutanoic acid

21. 2,2-dimethylpropanal

22. 2-phenylbutan-2-ol

23. 2-methylbutanamide

24. 3-methylbutan-2-amine

25. ethyl 2-methylbutanoate

26. 2,4-dimethylpentan-3-one

27. 3,3,5,5-tetramethylheptane

28. 3-ethylpentan-3-ol

29. hex-4-yn-3-one

30. octa-3,5-diene

31. 4-ethyl-5-methylhex-2-ene

32. 2-methoxypropanal

33. methyl 2-methylprop-2-enoate

34. 2,3-dihydroxybutanedioic acid

35. 3-methyl-2-oxobutanoic acid

36. 3-cyanopropanoic acid

37. 2-hydroxypropane-1,2,3-tricarboxylic acid

38. 5-ethoxy-4-methyl-5-oxopent-3-enoic acid

39. N-bromo-3-methyl-2-oxobutanamide

40. 4-chloro-3-methylbut-2-en-1-ol

41. 2-(bromomethyl)-3-oxopentanamide

42. 1-chloro-3,3-dimethylbutane

43. 2,3-dihydroxy-4-methylpentanal

44. 5-chloro-3-methylpentan-2-one

45. 4-hydroxypentan-2-one

46. 3-bromo-4-chloropentan-2-ol

47. 3-bromo-1,2-dichloropentan-3-ol

48. 5-chloro-3-ethylpentan-2-one

49. 2-chlorohex-5-ynal

50. 2-oxopropanal

51. 2-methoxy-4-methylpentan-3-one

52. 3-methylbut-3-en-1-ol

53. 3-phenylprop-2-enoic acid

54. 2-ethoxy-4-methoxypentan-3-one

55. propane-1,2,3-triol

56. 2-methoxybenzoic acid

57. phenyl 2-methylpropanoate



58. 2,3-dibromo-1-chloro-2-methylpentane

59. 2,4-dinitroaniline

60. 2-methoxy-2,3-dimethylbutanal

61. 2-methyl-4-oxobutanoic acid

62. ethyl 2-oxopropanoate

63. 1-methoxybutane-2,3-dione

64. N-chloro-N-ethylmethanamide

65. oxoethanoic acid

66. Cyclohexane

67. Cyclopentane

68. Cyclohexanol

69. 3-methylcyclohexanol

70. 1-methyl-3-nitrocyclohexene

71. 1-ethyl-2-methylcyclobutene

72. but-3-en-2-ylcyclopentane

73. 3-hydroxycyclohexanone

74. 1,5-dimethylcyclopentene

75. buta-1,3-diene

76. 4-methylpenta-1,3-diene

77. hexa-1,3,5-triene

78. pent-1-en-3-ol

79. 3-ethyl-4-methylpenta-1,3-diene

80. 6-ethyl-1-methylcyclohexa-1,3-diene

81. 2,6-dimethylhepta-2,5-dienoic acid

82. 2-bromopentan-3-one

83. 3-methylpent-4-enal

84. 2-ethenyl-3-methylcyclohexa-1,3-diene

85. 5,6-diethyldec-4-ene

86. 1-ethylcyclohexene

87. 5-methylcyclohex-2-ene-1-carboxylic acid

88. cyclohex-3-en-1-ol

89. 2-hydroxycyclopentanecarbaldehyde

90. 2,3-dimethylcyclohexanone

91. 1-bromo-2-chlorocyclobutene

92. 2-cyclobutylpropanal

93. 4-cyclopropylpentan-2-ol

94. 4-ethenyl-5-ethyloctane

95. 2-methylpropanoyl chloride

96. methyl propanoate

97. methyl 2-ethylbutanoate

98. 5-ethyl-4,6-dimethyloct-1-ene

99. butane-2,3-diol

100. 5,6-diethyl-8-methyldec-4-ene

101. 3-methylcyclopentanol

102. 7-ethyl-6-methylundec-6-enoic acid



103. ethyl propanoate

104. N-ethyl-N-methylpropan-1-amine

105. hex-3-yne

106. 3-ethyl-4-methylpentanal

107. benzene

108. naphthalene

109. anthracene

110. Phenanthrene

111. Diphenyl

112. Methylbenzene (Toluene)

113. 1,2-dimethylbenzene (o-Xylene)

114. 1,3-dimethylbenzene (m-Xylene)

115. 1,4-dimethylbenzene (p-Xylene)

116. Ethenylbenzene (vinyl benzene or styrene)

117. 1,3,5-trimethylbenzene

118. 1-chloro-3-methylbenzene

119. 1,4-dichlorobenzene

120. Phenyl chloromethane

121. 1-chloro-3-phenylpropane

122. 3-chloro-1-phenylprop-1-ene

123. phenol

124. benzene-1,2-diol (Catechol)

125. benzene-1,3-diol (Resorcinol)

126. benzene-1,4-diol (p-quinol or hydroquinone)

127. Phenylmethanol

128. 2-phenylethanol

129. Benzaldehyde

130. Phenylacetaldehyde

131. benzoic acid

132. 2-hydroxybenzoic acid

133. phenylethanoic acid

134. (2-hydroxyphenyl)acetic acid

135. benzene-1,2-dicarboxylic acid (phthalic acid)

136. benzene-1,3-dicarboxylic acid (isophthalic acid)

137. benzene-1,4-dicarboxylic acid (terephthalic acid)

138. 2-hydroxybenzoic acid (o-salicylic acid)

139. 2-methylbenzoic acid (o-toluic acid)

140. benzoyl chloride

141. Benzamide

142. benzene-1,2-dicarboxamide (phthalamide)

143. Phthalimide

144. benzoic anhydride

145. Phthalic anhydride

146. methyl benzoate

147. Aniline



148. N-methylaniline

149. N,N-dimethylaniline

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ch: 10 haloalkanes & haloarenes – … · 7. while naming the compounds containing functional...

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