Quiz 10

Question 1

If the conjugated diene is not symmetrical, what do you do?

Answer 1

Protonate to form the more stable carbocation

Question 2

The thermodynamic product predominates when the reaction is…

Answer 2

reversible

Question 3

The kinetic product predominates when the reaction is….

Answer 3

irreversible

1,2-addition

Question 4

most of the time, the 1,2 addition product is the …

Answer 4

kinetic product

Question 5

most of the time, the 1,4-addition product is the

Answer 5

thermodynamic product

Question 6

6) Which of the following pairs are resonance structures?

Answer 6

C) III

Question 7

7) Which of the following pairs are resonance structures?

Answer 7

C) III

Question 8

8) Which of the following is not a resonance structure of the species shown?

Answer 8

D) IV

Question 12

9) In which of the following does resonance delocalization of electron density not play a role?

A) allyl cation

B) benzyl anion

C) CO32-

D) O3

E) cyclohexyl radical

Answer 12

E) cyclohexyl radical

Question 13

11) Due to electron delocalization, one would predict that the carbon-oxygen bond in acetamide, CH3CONH2, ________.

A) is nonpolar

B) has more double bond character than the carbon-oxygen bond of acetone, (CH3)2CO

C) is longer than the carbon-oxygen bond of dimethyl ether, (CH3)2O

D) is longer than the carbon-oxygen bond of acetone, (CH3)2CO

E) is formed by overlapping sp3 orbitals

Answer 13

D) is longer than the carbon-oxygen bond of acetone, (CH3)2CO

Question 14

33) Identify the most stable structure(s).

Answer 14

Answer: A

Question 15

36) Which of the following statements concerning resonance contributors and resonance hybrids is not correct?

A) The fewer nearly equivalent resonance contributors are in the structure, the greater the resonance energy.

B) A resonance hybrid is more stable than the predicted stability of any of its resonance contributors.

C) The greater the number of relatively stable resonance contributors, the greater the resonance energy.

D) The greater the predicted stability of a resonance contributor, the more it contributes to the resonance hybrid.

E) none of the above

Answer 15

A) The fewer nearly equivalent resonance contributors are in the structure, the greater the resonance energy.

Question 16

38) Aromatic molecules contain ________ π electrons.

A) no

B) 4n + 2 (with n an integer)

C) 4n + 2 (where n = 0.5)

D) 4n (with n an integer)

E) unpaired

Answer 16

B) 4n + 2 (with n an integer)

Question 17

43) Which of the following is an aromatic hydrocarbon?

Answer 17

C) III

Question 18

44) Which of the following is aromatic?

Answer 18

C) III

Question 19

45) Which of the structures below would be aromatic?

Answer 19

C) III and IV

Question 20

46) Which of the following is aromatic?

Answer 20

B) II

Question 21

47) Which of the following is aromatic?

A) cyclopentadienyl cation

B) 1,3-cyclohexadiene

C) cyclobutenyl anion

D) 1,3,5-hexatriene

E) cycloheptatrienyl cation

Answer 21

E) cycloheptatrienyl cation

Question 22

49) Which of the following compounds is aromatic?

Answer 22

D) IV

Question 23

50) Which of the following is aromatic?

Answer 23

A) I

Question 24

55) Which of the following is antiaromatic?

Answer 24

D) IV

Question 25

64) Which of the following statements about the π molecular orbital description of cyclobutadiene is not correct?

A) Cyclobutadiene has two degenerate nonbonding π molecular orbitals.

B) Cyclobutadiene has a single bonding π molecular orbital.

C) Cyclobutadiene has two electrons in nonbonding π molecular orbitals.

D) Cyclobutadiene has one electron in an antibonding π molecular orbital which makes it antiaromatic.

E) none of the above

Answer 25

D) Cyclobutadiene has one electron in an antibonding π molecular orbital which makes it antiaromatic.

Question 26

66) Which of the following is an allylic cation?

Answer 26

B) II

Question 27

67) Which of the following is a benzylic cation?

Answer 27

D) IV

Question 28

68) Which of the following is the most stable cation?

Answer 28

C) III

Question 29

69) How many allylic hydrogen atoms are present in the following molecule?

Answer 29

E) zero

Question 30

70) How many benzylic hydrogens are present in the following molecule?

Answer 30

E) zero

Question 31

71) Which of the following is the most stable diene?

Answer 31

C) III

Question 32

74) What descriptive term is applied to the type of diene represented by 2,4-hexadiene? A) conjugated diene B) cumulated diene C) isolated diene D) alkynyl diene E) none of the above

Answer 32

A) conjugated diene

Question 33

75) What descriptive term is applied to the type of diene represented by 1, 5-octadiene? A) conjugated diene B) cumulated diene C) isolated diene D) alkynyl diene E) none of the above

Answer 33

C) isolated diene

Question 34

76) Which of the following is a cumulated diene?

Answer 34

C) III

Question 35

77) Which of the following is a conjugated diene?

Answer 35

A) I

Question 36

86) Identify the most stable carbocation.

Answer 36

Question 37

87) Identify the most stable carbocation.

Answer 37

Question 38

96) Which of the following is/are the major product(s) of the following reaction?

Answer 38

A) I

Question 39

97) Which of the following is the strongest acid?

Answer 39

Question 40

98) Which of the following is the strongest acid?

Answer 40

D) IV

Question 41

103) Which of the following is/are the main product(s) of the following reaction?

Answer 41

E) A and C

Question 42

104) What is/are the product(s) from the following reaction?

Answer 42

D) I is major, II is minor

Question 43

105) What is/are the product(s) of the following reaction?

Answer 43

E) I and III

Question 44

106) What compound results from the 1, 4-addition of one equivalent of HBr to 1, 3-butadiene? A) 1-bromo-1-butene B) 2-bromo-2-butene C) 4-bromo-1-butene D) 3-bromo-1-butene E) 1-bromo-2-butene

Answer 44

E) 1-bromo-2-butene

Question 45

107) Which of the following is/are the major product(s) of the following reaction?

Answer 45

C) II

Question 46

108) What is/are the product(s) from the following reaction?

Answer 46

A) I and II

Question 47

111) Give the major organic product for the reaction.

Answer 47

Question 48

112) Give the major organic product for the reaction.

Answer 48

Question 49

113) Give the major organic product(s) for the reaction.

Answer 49

Answer: A, B

Question 50

115) Give the major organic product(s) for the reaction.

Answer 50

Answer: D, E

Question 51

117) What is the thermodynamic product for the following reaction?

Answer 51

D) IV

Question 52

118) What is the kinetic product for the following reaction?

Answer 52

E) V

Question 53

119) Which of the following is a correct statement considering thermodynamic versus kinetic control of organic reactions? A) When a reaction is under thermodynamic control, the relative amounts of products depend on the activation energies of the steps leading to their formation. B) The kinetic product always predominates when the reaction is reversible. C) Higher temperatures and longer reaction times typically favor the kinetic product over the thermodynamic product. D) When the products are in equilibrium under the reaction conditions, the relative amounts of products depend on their stabilities and the reaction is under thermodynamic control. E) none of the above

Answer 53

D) When the products are in equilibrium under the reaction conditions, the relative amounts of products depend on their stabilities and the reaction is under thermodynamic control.

Question 54

120) What is/are the product(s) from the following reaction?

Answer 54

B) II Major, III Minor

Question 55

121) What is/are the product(s) from the following reaction?

Answer 55

C) III only

Question 56

128) What is the product of the following reaction?

Answer 56

E) V

Question 57

129) What is the product from the following reaction?

Answer 57

B) II

Question 58

130) Which of the following conjugated dienes would not react with a dieneophile in a Diels-Alder reaction?

Answer 58

E) I and III

Question 59

131) Which of the following dienes is the most reactive in a Diels-Alder reaction?

Answer 59

C) III

Question 60

132) What diene and what dieneophile would be used to synthesize the following compound?

Answer 60

B) II

Question 61

133) Which of the following terms best describes a Diels-Alder reaction? A) a [4+2] cycloaddition B) a [2+2] cycloaddition C) a sigmatropic rearrangement D) a 1, 3-dipolar cycloaddition E) a substitution reaction

Answer 61

A) a [4+2] cycloaddition

Question 62

134) When 1, 3-butadiene reacts with CH2CHCN, which of the terms below best describes the product mixture? A) a mixture of two diastereomers B) a single compound C) a racemic mixture D) optically active E) a mixture of bicyclic compounds

Answer 62

C) a racemic mixture

Question 63

135) The Diels-Alder reaction is a concerted reaction; this means that \_\_\_\_\_\_\_\_. A) a mixture of endo and exo products is formed B) all bond making and bond breaking occurs simultaneously C) the products contain rings D) the reaction follows Markovnikov's rule E) the reaction is highly endothermic

Answer 63

B) all bond making and bond breaking occurs simultaneously

Question 64

136) Which of the following statements is (are) true of the Diels-Alder reaction? A) When the diene is electron-rich, the reaction works best when the dienophile contains one or more electron-withdrawing groups conjugated to its CC. B) Substituents which are cis in the dienophile remain cis in the product. C) Dienes which cannot achieve an s-cis conformation do not react in Diels-Alder reactions. D) Secondary orbital interactions typically cause the endo product to be favored kinetically over the exo. E) all of the above

Answer 64

E) all of the above

Question 65

137) When 1, 3-cyclopentadiene reacts with the cis-isomer of NCCH=CHCN, the major product is \_\_\_\_\_\_\_\_. A) optically active B) a meso compound C) a racemic mixture D) a spirocyclic compound E) a fused bicyclic compound

Answer 65

D) a spirocyclic compound

Question 66

158) Give the major organic product for the reaction.

Answer 66

Question 67

159) Give the major organic product for the reaction.

Answer 67

Question 68

160) Give the major organic product for the reaction.

Answer 68

E) No reaction

Question 69

164) Which of the following is an isolated diene?

Answer 69

D) IV

Question 70

166) Give the major organic product for the reaction.

Answer 70

Question 72

If the conjugated diene is not symmetrical, what do you do?

Answer 72

Protonate to form the more stable carbocation

Question 73

The thermodynamic product predominates when the reaction is...

Answer 73

reversible

Question 74

The kinetic product predominates when the reaction is....

Answer 74

irreversible 1,2-addition

Question 75

most of the time, the 1,2 addition product is the ...

Answer 75

kinetic product

Question 76

most of the time, the 1,4-addition product is the

Answer 76

thermodynamic product

Question 77

6) Which of the following pairs are resonance structures?

Answer 77

C) III

Question 78

7) Which of the following pairs are resonance structures?

Answer 78

C) III

Question 79

8) Which of the following is not a resonance structure of the species shown?

Answer 79

D) IV

Question 81

22. Which of the following reaction coordinate diagrams explains the formation of different thermodynamic (T) and kinetic products from the same reactants (R)?

Answer 81

C. 3

Question 84

9) In which of the following does resonance delocalization of electron density not play a role? A) allyl cation B) benzyl anion C) CO32- D) O3 E) cyclohexyl radical

Answer 84

E) cyclohexyl radical

Question 86

What is the reactive intermediate in the reaction of 1,3-butadiene with HBr resulting in 1,2-addition? A. cyclic bromonium cation B. allylic cation C. allylic radical D. dienophile

Answer 86

B. allylic cation

Question 87

Answer 87

C. only 1 and 2

Question 88

Answer 88

B. only 2

Question 89

Answer 89

C. 3,4-dimethyl-1,3-pentadiene

Question 90

Answer 90

C. 3-methyl-1,4-pentadiene

Question 91

Answer 91

A. (3S,4E)-3-ethyl-3,4-dimethyl-1,4-hexadiene

Question 92

Answer 92

C. 3

Question 93

Answer 93

B. 3 \> 1 \> 2

Question 94

Answer 94

D. only 1 and 4

Question 95

Answer 95

B. only 1 and 2

Question 96

Answer 96

C. only 2 and 4

Question 97

Answer 97

B. only 2

Question 98

Answer 98

B. only 3

Question 99

Answer 99

C. only 3

Question 100

Which of the following terms describes the mechanism for the addition of Br2 to butadiene? A. electrophilic addition B. nucleophilic addition C. pericyclic addition D. conjugate addition

Answer 100

A. electrophilic addition

Question 101

Which of the following is not a major organic product obtained from the addition of 1 mole of bromine to (E)-1,3-pentadiene? A. (E)-4,5-dibromo-2-pentene B. 3,4-dibromo-1-pentene C. (E)-1,4-dibromo-2-pentene D. (E)-1,2-dibromo-2-pentene

Answer 101

D. (E)-1,2-dibromo-2-pentene

Question 102

What is the thermodynamic product obtained from the addition of 1 mole of bromine to 1,3-butadiene? A. 3,4-dibromo-1-butene B. (E)-1,4-dibromo-2-butene C. (Z)-1,4-dibromo-2-butene D. (Z)-2,3-dibromo-2-butene

Answer 102

B. (E)-1,4-dibromo-2-butene

Question 103

What is the kinetic product obtained from the addition of 1 mole of bromine to 1,3-butadiene? A. 3,4-dibromo-1-butene B. (E)-1,4-dibromo-2-butene C. (Z)-1,4-dibromo-2-butene D. (Z)-2,3-dibromo-2-butene

Answer 103

A. 3,4-dibromo-1-butene