Deck 13: Conjugated Unsaturated Systems

Question 1

The allyl radical has how many electrons in non-bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Answer 1

1

Question 2

The allyl cation has how many bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Answer 2

1

Question 3

The LUMO of 1,3-pentadiene has how many electrons in its ground state?

A)1
B)2
C)3
D)4
E)0

Answer 3

0

Question 4

The HOMO of 1,3-pentadiene has how many electrons in its ground state?

A)1
B)2
C)3
D)4
E)0

Question 5

The allyl radical has how many electrons in bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Question 6

The allyl cation has how many $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Question 7

The LUMO of 1,3-pentadiene has how many electrons in its excited state?

A)1
B)2
C)3
D)4
E)0

Question 8

1,3-Butadiene has how many electrons in its ground state bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)0

Question 9

1,3-Butadiene has how many electrons in its ground state antibonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)0

Question 10

Which carbocation would be least stable?

A)I
B)II
C)III
D)IV
E)V

Question 11

The HOMO of 1,3-pentadiene has how many electrons in its excited state?

A)1
B)2
C)3
D)4
E)0

Question 12

The HOMO of the allylic cation has how many electrons in its ground state?

A)1
B)2
C)3
D)4
E)0

Question 13

The allyl radical has how many bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Question 14

1,3-Pentadiene has how many bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)0

Question 15

The LUMO of the allylic radical has how many electrons in its ground state?

A)1
B)2
C)3
D)4
E)0

Question 16

The HOMO of the allylic radical has how many electrons in its ground state?

A)1
B)2
C)3
D)4
E)0

Question 17

The allyl cation has how many electrons in bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Question 18

The allyl radical has how many $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)5

Question 19

1,3-Pentadiene has how many antibonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)0

Question 20

1,3-Butadiene has how many bonding $\pi$ molecular orbitals?

A)1
B)2
C)3
D)4
E)0

Question 21

Considering both configurational and conformational factors,select the least stable form of 2,4-hexadiene.

A)I
B)II
C)III
D)IV
E)V

Question 22

Which carbocation would be least stable?

A)I
B)II
C)III
D)IV
E)V

Question 23

Arrange these carbocations in order of expected increasing stability.

A)V < II < I < IV < III
B)V < I < II < IV < III
C)IV D)IV < III < I < II < V
E)II < III < IV < V < I

Question 24

Which of the following dienes would you expect to be the most stable?

A)CH₃CH₂CH=CHCH₂CH=CHCH₃
B)CH₃CH=CHCH=CHCH₂CH₃
C)CH₂=CHCH₂CH₂CH₂CH=CH₂
D)CH₂=CHCH=CHCH₂CH₂CH₃
E)CH₃CH=C(CH₃)CH=CHCH₂CH₃

Question 25

Which diene would be least stable?

A)I
B)II
C)III
D)IV
E)V

Question 26

Which carbocation would be most stable?

A)I
B)II
C)III
D)IV
E)V

Question 27

Arrange these hexadienes in order of expected increasing stability.

A)V < II < I < III < IV
B)III < IV < II < I < V
C)IV < III < II < V < I
D)IV < III < I < II < V
E)I < II < IV < III < V

Question 28

Which alkene would you expect to be most stable?

A)CH₂=CHCH₂CH₂CH=CH₂
B)
C)
D)
E)

Question 29

Which of the following dienes would you expect to be the most stable?

A)CH₃CH₂CH=CHCH₂CH=CHCH₃
B)CH₃CH=CHCH=CHCH₂CH₃
C)CH₂=CHCH₂CH₂CH₂CH=CH₂
D)CH₂=CHCH=CHCH₂CH₂CH₃
E)CH₃CH₂CH=C=CHCH₂CH₃

Question 30

Which of the following dienes would you expect to be the most stable?

A)CH₃CH=CHCH=CHCH₃
B)CH₃CH=CHCH₂CH=CH₂
C)CH₂=CHCH₂CH₂CH=CH₂
D)CH₂=CHCH(CH₃)CH=CH₂
E)CH₃CH=C=CHCH₂CH₃

Question 31

Arrange these hexadienes in order of expected decreasing stability.

A)V > II > I > III > IV
B)III > IV > II > I > V
C)IV > III > II > V > I
D)IV > III > I > II > V
E)I > II > IV > III > V

Question 32

Which of the following dienes would you expect to be the least stable?

A)CH₃CH₂CH=CHCH₂CH=CHCH₃
B)CH₃CH=CHCH=CHCH₂CH₃
C)CH₂=CHCH₂CH₂CH₂CH=CH₂
D)CH₂=CHCH=CHCH₂CH₂CH₃
E)CH₃CH=C(CH₃)CH=CHCH₂CH₃

Question 33

Which of the following compounds would be the most stable?

A)I
B)II
C)III
D)IV
E)They are all of equal stability.

Question 34

Arrange these carbocations in order of expected increasing stability.

A)V < II < I < IV < III
B)V < I < II < IV < III
C)IV < I < II < V < III
D)IV < III < I < II < V
E)I < II < IV < III < V

Question 35

Which carbocation would be most stable?

A)I
B)II
C)III
D)IV
E)V

Question 36

Considering both configurational and conformational factors,select the most stable form of 2,4-hexadiene.

A)I
B)II
C)III
D)IV
E)V

Question 37

Which carbocation would be most stable?

A)
B)
C)
D)
E)

Question 38

Which carbocation would be least stable?

A)
B)
C)
D)
E)

Question 39

Which is not an example of resonance?

A)I
B)II
C)III
D)IV
E)None of these choices are examples of resonance.

Question 40

Which carbocation would be most stable?

A)I
B)II
C)III
D)IV
E)V

Question 41

Which of the following dienes is a cumulated diene?

A)CH₂=CHCH₂CH₂CH₂CH=CH₂
B)CH₂=CHCH=CHCH₂CH₂CH₃
C)CH₃CH=C=CHCH₂CH₂CH₃
D)CH₃CH=CHCH=CHCH₂CH₃
E)CH₃CH₂CH=CHCH₂CH=CH₂

Question 42

Which pair does not represent a pair of resonance structures?

A)I
B)II
C)III
D)IV
E)All of these choices represent pairs of resonance structures.

Question 43

Select the structure of the conjugated diene.

A)I
B)II
C)III
D)IV
E)V

Question 44

The substituent R on the bicyclic compound shown is considered to be?

A)axial
B)equatorial
C)endo
D)exo
E)trans

Question 45

Which is not a proper resonance structure for 1,3-butadiene?

A)CH₂=CH-CH=CH₂
B)
C)
D)
E)All of these answer choices are correct.

Question 46

Select the structure of the conjugated diene.

A)I
B)II
C)III
D)IV
E)V

Question 47

Which of the following dienes is a cumulated diene?

A)CH₂=CHCH₂CH₂CH=CH₂
B)CH₂=CHCH=CHCH₂CH₃
C)CH₃CH=C=CHCH₂CH₃
D)CH₃CH=CHCH=CHCH₃
E)CH₃CH=CHCH₂CH=CH₂

Question 48

Which pair does not represent a pair of resonance structures?

A)I
B)II
C)III
D)IV
E)All of these choices represent pairs of resonance structures.

Question 49

Select the structure of the conjugated diene.

A)I
B)II
C)III
D)IV
E)V

Question 50

The substituent R on the bicyclic compound shown is considered to be?

A)axial
B)equatorial
C)endo
D)exo
E)trans

Question 51

Which is not an example of resonance?

A)I
B)II
C)III
D)IV
E)None of these choices are examples of resonance.

Question 52

Which pair does not represent a pair of resonance structures?

A)I
B)II
C)III
D)IV
E)All of these choices represent pairs of resonance structures.

Question 53

A correct IUPAC name of the compound below is:

A)1-Bromo-1-methyl-2,5-cyclohexadiene
B)3-Bromo-3-methyl-1,4-cyclohexadiene
C)6-Bromo-6-methyl-1,4-cyclohexadiene
D)2-Bromo-2-methyl-1,3-cyclohexadiene
E)None of these choices.

Question 54

Which pair does not represent a pair of resonance structures?

A)I
B)II
C)III
D)IV
E)All of these choices represent pairs of resonance structures.

Question 55

Select the structure(s)in which the multiple bonds are conjugated.

A)I and II
B)II and III
C)III and IV
D)I,II and V
E)V

Question 56

Select the structure(s)in which the multiple bonds are conjugated.

A)I and IV
B)II and III
C)III and V
D)I,II and III
E)V

Question 57

Which pair does not represent a pair of resonance structures?

A)I
B)II
C)III
D)IV
E)All of these choices represent pairs of resonance structures.

Question 58

Select the structure(s)of the conjugated diene(s).

A)I and II
B)II and III
C)III and IV
D)I,II and V
E)V

Question 59

Select the structure of the isolated diene.

A)I
B)II
C)III
D)IV
E)V

Question 60

What is an IUPAC name for

A)2,3-methylhept-2-en-4-yne
B)1,1,3-trimethylhex-3-yn-1-ene
C)1,1,3-trimethyl-3-hexyn-1-ene
D)2,3-dimethyl-2-hepten-4-yne
E)5,6-dimethyl-5-hepten-3-yne

Question 61

The substituent R on the bicyclic compound shown is considered to be?

A)axial
B)equatorial
C)endo
D)exo
E)trans

Question 62

Which compound would have the shortest carbon-carbon single bond?

A)CH $\equiv$ C-CH=CH-CH₂-CH₃
B)CH₂=CH-CH=CH-CH₃
C)HC $\equiv$ C-CH₂-C $\equiv$ C-CH₃
D)CH₂=CH-C $\equiv$ C-CH₂-CH₃
E)CH₃-C $\equiv$ C-C $\equiv$ C-CH₃

Question 63

Which carbon-carbon bond in the following compound would you expect to be shortest?

A)I
B)II
C)III
D)IV
E)V

Question 64

Which alkene would you expect to have the highest heat of hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 65

The substituent R on the bicyclic compound shown is considered to be?

A)axial
B)equatorial
C)endo
D)exo
E)trans

Question 66

Which alkene would you expect to have the smallest heat of hydrogenation?

A)
B)
C)
D)
E)

Question 67

Which alkene would you expect to have the lowest heat of hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 68

The substituent R on the bicyclic compound shown is considered to be?

A)axial
B)equatorial
C)endo
D)exo
E)trans

Question 69

Which carbon-carbon bond in the following compound would you expect to be longest?

A)I
B)II
C)III
D)IV
E)V

Question 70

The substituent R on the bicyclic compound shown is considered to be?

A)axial
B)equatorial
C)endo
D)exo
E)Trans

Question 71

Which compound would have a UV absorption band at longest wavelength?

A)I
B)II
C)III
D)IV
E)V

Question 72

Which compound would have the shortest carbon-carbon single bond?

A)CH₃-CH₃
B)CH₂=CH-CH₃
C)HC $\equiv$ C-C $\equiv$ CH
D)CH₂=CH-C $\equiv$ CH
E)CH₂=CH-CH=CH₂

Question 73

What is an IUPAC name for this triene?

A)(2E,4Z,6E)-3,4,7,8-tetramethyl-2,4,6-Nonatriene
B)(2Z,4E,6E)-3,4,7,8-tetramethyl-2,4,6-Nonatriene
C)(2E,4Z,6E)-2,3,6,7-tetramethyl-3,5,7-Nonatriene
D)(2E,4Z,6E)-2,3,6,7-tetramethyl-3,5,7-nonatriene
E)(2E,4E,6E)-3,4,7,8-tetramethyl-2,4,6-Nonatriene

Question 74

Which alkene would you expect to have the lowest heat of hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 75

Which alkene would you expect to have the lowest heat of hydrogenation?

A)I
B)II
C)III
D)IV
E)V

Question 76

Which compound would have a UV absorption band at longest wavelength?

A)I
B)II
C)III
D)IV
E)V

Question 77

Which compound would have a UV absorption band at longest wavelength?

A)I
B)II
C)III
D)IV
E)V

Question 78

Which alkene would you expect to have the smallest heat of hydrogenation?

A)CH₂=CHCH₂CH₂CH=CH₂
B)
C)
D)
E)

Question 79

What is an IUPAC name for this triene?

A)(2E,4Z,6E)-2,4,6-Nonatriene
B)(2Z,4E,6Z)-2,4,6-Nonatriene
C)(2E,4Z,6Z)-2,4,6-Nonatriene
D)(3Z,5Z,7E)-3,5,7-Nonatriene
E)(3Z,5E,7E)-3,5,7-Nonatriene

Question 80

Which alkene would you expect to have the highest heat of hydrogenation?

A)
B)
C)
D)
E)