CHAPTER 23
Organic Chemistry
■ SOLUTIONS TO EXERCISES
23.1. The condensed structural formula is
CH3
CH3CHCH2CH3
23.2. a. Geometric isomers are possible.
H H H CH2CH2CH3
C C C C
H
CH3 CH2CH2CH3 CH3
cis-2-Hexene trans-2-Hexene
b. No geometric isomers are possible because there are two H atoms attached to the second
carbon of the double bond.
23.3. According to Markownikoff's rule, when HBr is added across the double bond in 1-butene, the H
will add to carbon 1 (the C atom with the most bonds to H atoms) and the Br will add to carbon 2.
H2C CH CH2 CH3 + HBr H3C CH CH2 CH3
Br
The product is 2-bromobutane.
23.4. a. The longest continuous chain is numbered as follows:
CH3
1 2 3 4
CH3CHCHCH3
CH3
The name of the compound is 2,3-dimethylbutane.
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, Chapter 23: Organic Chemistry 913
b. To give the substituents the smaller numbers, the longest continuous chain is numbered as
follows:
4 5 6
CH2CH2 CH3
1 2 3
CH3CHCHCH2CH3
CH3
The name of the compound is 3-ethyl-2-methylhexane.
23.5. First write out the carbon skeleton for octane.
1 2 3 4 5 6 7 8
—C—C—C—C—C—C —C—C—
Then attach the alkyl groups.
CH3
1 2 3 4 5 6 7 8
—C—C—C—C—C—C —C—C—
CH3
Finally, fill out the structure with H atoms.
23.6. a. The numbering of the carbon chain is
1 2 3 4
CH3C = CHCHCH3
5
CH3 CH2
6
CH3
Because the longest chain containing a double bond has six carbons, this is a hexene. It is a
2-hexene because the double bond is between carbons 2 and 3. The name of the compound
is 2,4-dimethyl-2-hexene.
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, 914 Chapter 23: Organic Chemistry
b. The numbering of the longest chain with a double bond is
6 5 4 3
CH3CH2 CH2 CHCH2 CH2CH3
2
CH
1
CH2
The longest chain containing the double bond has six carbon atoms; therefore, this is a
hexene. It is a 1-hexene because the double bond is between carbons 1 and 2. The name of
the compound is 3-propyl-1-hexene.
23.7. First write out the carbon skeleton for 2-heptene.
1 2 3 4 5 6 7
—C—C = C—C—C—C—C
Then add the alkyl groups.
C—C = C—C—C—C—C
CH3 CH3
Finally, add the H atoms.
23.8. The two isomers of CH3CH2CH ═ CHCH2CH3 are cis-3-hexene and trans-3-hexene.
23.9. a. There are only three carbons in the chain. The compound is propyne.
b. The longest continuous chain containing the triple bond has five carbon atoms. The
compound is 3-methyl-1-pentyne.
23.10. a. This compound has an ethyl group attached to a benzene ring.
CH2CH3
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Organic Chemistry
■ SOLUTIONS TO EXERCISES
23.1. The condensed structural formula is
CH3
CH3CHCH2CH3
23.2. a. Geometric isomers are possible.
H H H CH2CH2CH3
C C C C
H
CH3 CH2CH2CH3 CH3
cis-2-Hexene trans-2-Hexene
b. No geometric isomers are possible because there are two H atoms attached to the second
carbon of the double bond.
23.3. According to Markownikoff's rule, when HBr is added across the double bond in 1-butene, the H
will add to carbon 1 (the C atom with the most bonds to H atoms) and the Br will add to carbon 2.
H2C CH CH2 CH3 + HBr H3C CH CH2 CH3
Br
The product is 2-bromobutane.
23.4. a. The longest continuous chain is numbered as follows:
CH3
1 2 3 4
CH3CHCHCH3
CH3
The name of the compound is 2,3-dimethylbutane.
© 2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
, Chapter 23: Organic Chemistry 913
b. To give the substituents the smaller numbers, the longest continuous chain is numbered as
follows:
4 5 6
CH2CH2 CH3
1 2 3
CH3CHCHCH2CH3
CH3
The name of the compound is 3-ethyl-2-methylhexane.
23.5. First write out the carbon skeleton for octane.
1 2 3 4 5 6 7 8
—C—C—C—C—C—C —C—C—
Then attach the alkyl groups.
CH3
1 2 3 4 5 6 7 8
—C—C—C—C—C—C —C—C—
CH3
Finally, fill out the structure with H atoms.
23.6. a. The numbering of the carbon chain is
1 2 3 4
CH3C = CHCHCH3
5
CH3 CH2
6
CH3
Because the longest chain containing a double bond has six carbons, this is a hexene. It is a
2-hexene because the double bond is between carbons 2 and 3. The name of the compound
is 2,4-dimethyl-2-hexene.
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, 914 Chapter 23: Organic Chemistry
b. The numbering of the longest chain with a double bond is
6 5 4 3
CH3CH2 CH2 CHCH2 CH2CH3
2
CH
1
CH2
The longest chain containing the double bond has six carbon atoms; therefore, this is a
hexene. It is a 1-hexene because the double bond is between carbons 1 and 2. The name of
the compound is 3-propyl-1-hexene.
23.7. First write out the carbon skeleton for 2-heptene.
1 2 3 4 5 6 7
—C—C = C—C—C—C—C
Then add the alkyl groups.
C—C = C—C—C—C—C
CH3 CH3
Finally, add the H atoms.
23.8. The two isomers of CH3CH2CH ═ CHCH2CH3 are cis-3-hexene and trans-3-hexene.
23.9. a. There are only three carbons in the chain. The compound is propyne.
b. The longest continuous chain containing the triple bond has five carbon atoms. The
compound is 3-methyl-1-pentyne.
23.10. a. This compound has an ethyl group attached to a benzene ring.
CH2CH3
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