Question 1

Which annulene would you NOT expect to be aromatic?

Accepted Answer

A) [6]Annulene 
B) [14]Annulene 
C) [16]Annulene 
D) [18]Annulene 
E) [22]Annulene 
A) [6]Annulene 
B) [14]Annulene 
C) [16]Annulene 
D) [18]Annulene 
E) [22]Annulene

Question 2

The Lewis structures of both pyridine and pyrrole have an electron pair on the nitrogen atom,suggesting that both substances might possess basic properties.However,only pyridine reacts readily with HCl to form pyridinium chloride,while pyrrole is rather unreactive.Explain clearly,using relevant diagrams to illustrate/clarify your answer.

Accepted Answer

@#IMG-DLM&
 Both pyridine and pyrrole are known to

Question 3

4-Amino-2-chlorobenzaldehyde is:

Accepted Answer

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

Question 4

Briefly explain why the aromatic hydrocarbon shown possesses a significant dipole moment.Use diagrams as needed to illustrate/clarify your answer.

Accepted Answer

@#IMG-DLM& The stable,low energy resonan

Question 5

Consider the molecular orbital model of cyclopentadienyl anion.In the ground state how many molecular orbitals are filled with electrons?

Accepted Answer

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

Question 6

Which of the following would you expect to be aromatic?

Accepted Answer

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

Question 7

Which of the following statements regarding the cyclopentadienyl radical is correct?

Accepted Answer

A) It is aromatic. 
B) It is not aromatic. 
C) It obeys Hückel's rule. 
D) It undergoes reactions characteristic of benzene. 
E) It has a closed shell of 6 pi electrons. 
A) It is aromatic. 
B) It is not aromatic. 
C) It obeys Hückel's rule. 
D) It undergoes reactions characteristic of benzene. 
E) It has a closed shell of 6 pi electrons.

Question 8

How many resonances would be expected in the broadband proton-decoupled 13C spectrum of:

Accepted Answer

A) 4 
B) 5 
C) 6 
D) 7 
E) 8 
A) 4 
B) 5 
C) 6 
D) 7 
E) 8

Question 9

In which of the following compounds would the shortest carbon-carbon bond(s)be found?

Accepted Answer

A) Toluene 
B) 2-Ethylcyclopentene 
C) 4-Methyl-1,3-cyclohexadiene 
D) 3-Methyl-1-hexyne 
E) 3-Methyl-1,3-hexadiene 
A) Toluene 
B) 2-Ethylcyclopentene 
C) 4-Methyl-1,3-cyclohexadiene 
D) 3-Methyl-1-hexyne 
E) 3-Methyl-1,3-hexadiene

Question 10

Which of the following statements about cyclooctatetraene is NOT true?

Accepted Answer

A) The compound rapidly decolorizes Br2/CCl4 solutions. 
B) The compound rapidly decolorizes aqueous solutions of KMnO4. 
C) The compound readily adds hydrogen. 
D) The compound is nonplanar. 
E) The compound is comparable to benzene in stability. 
A) The compound rapidly decolorizes Br2/CCl4 solutions. 
B) The compound rapidly decolorizes aqueous solutions of KMnO4. 
C) The compound readily adds hydrogen. 
D) The compound is nonplanar. 
E) The compound is comparable to benzene in stability.

Question 11

In the molecular orbital model of cycloheptadienyl cation,how many pi electrons are delocalized about the ring?

Accepted Answer

A) 6 
B) 5 
C) 4 
D) 3 
E) 2 
A) 6 
B) 5 
C) 4 
D) 3 
E) 2

Question 12

How many resonances would be expected in the broadband proton-decoupled 13C spectrum of:

Accepted Answer

A) 4 
B) 5 
C) 6 
D) 7 
E) 8 
A) 4 
B) 5 
C) 6 
D) 7 
E) 8

Question 13

Which of the following would you expect to be antiaromatic?

Accepted Answer

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

Question 14

Which isomer of C7H7Cl exhibits strong IR absorbances at 690 and 750 cm-1?

Accepted Answer

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

Question 15

Cycloheptatriene is found to readily undergo a hydride transfer with triphenylmethyl arbocation to generate the cycloheptatrienyl cation and triphenylmethane.Explain why this transformation is facile.

Accepted Answer

This reaction readily proceeds

Question 16

Which of these would you expect to have significant resonance stabilization energy?

Accepted Answer

A) I 
B) II 
C) III 
D) All of these choices. 
E) None of these choices. 
A) I 
B) II 
C) III 
D) All of these choices. 
E) None of these choices.

Question 17

Recalling that benzene has a resonance energy of 152 kJ mol-1 and naphthalene has a resonance energy of 255 kJ mol-1,predict the positions which would be occupied by bromine when phenanthrene (below)undergoes addition of Br2.

Accepted Answer

A) 1,2 
B) 1,4 
C) 3,4 
D) 7,8 
E) 9,10 
A) 1,2 
B) 1,4 
C) 3,4 
D) 7,8 
E) 9,10

Question 18

Toluene is the name commonly assigned to:

Accepted Answer

A) Hydroxybenzene 
B) Aminobenzene 
C) Methylbenzene 
D) Ethylbenzene 
E) Methoxybenzene 
A) Hydroxybenzene 
B) Aminobenzene 
C) Methylbenzene 
D) Ethylbenzene 
E) Methoxybenzene

Question 19

If thiophene is an aromatic molecule and reacts similarly to benzene,how many (neutral)monobromothiophenes could be obtained in the following reaction?

Accepted Answer

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

Question 20

On the basis of molecular orbital theory and Hückel's rule,which molecules and/or ions should be aromatic?

Accepted Answer

A) I and V 
B) III and VIII 
C) IV,VII and IX 
D) IV,VI,VII and IX 
E) All of the structures,I-IX 
A) I and V 
B) III and VIII 
C) IV,VII and IX 
D) IV,VI,VII and IX 
E) All of the structures,I-IX

Exam 14: Aromatic Compounds

Which annulene would you NOT expect to be aromatic?

4-Amino-2-chlorobenzaldehyde is:

Briefly explain why the aromatic hydrocarbon shown possesses a significant dipole moment.Use diagrams as needed to illustrate/clarify your answer.

Consider the molecular orbital model of cyclopentadienyl anion.In the ground state how many molecular orbitals are filled with electrons?

Which of the following would you expect to be aromatic?

Which of the following statements regarding the cyclopentadienyl radical is correct?

How many resonances would be expected in the broadband proton-decoupled 13C spectrum of:

In which of the following compounds would the shortest carbon-carbon bond(s)be found?

Which of the following statements about cyclooctatetraene is NOT true?

In the molecular orbital model of cycloheptadienyl cation,how many pi electrons are delocalized about the ring?

How many resonances would be expected in the broadband proton-decoupled 13C spectrum of:

Which of the following would you expect to be antiaromatic?

Which isomer of C7H7Cl exhibits strong IR absorbances at 690 and 750 cm-1?

Cycloheptatriene is found to readily undergo a hydride transfer with triphenylmethyl arbocation to generate the cycloheptatrienyl cation and triphenylmethane.Explain why this transformation is facile.

Which of these would you expect to have significant resonance stabilization energy?

Recalling that benzene has a resonance energy of 152 kJ mol-1 and naphthalene has a resonance energy of 255 kJ mol-1,predict the positions which would be occupied by bromine when phenanthrene (below)undergoes addition of Br2.

Toluene is the name commonly assigned to:

If thiophene is an aromatic molecule and reacts similarly to benzene,how many (neutral)monobromothiophenes could be obtained in the following reaction?

On the basis of molecular orbital theory and Hückel's rule,which molecules and/or ions should be aromatic?

The Basics

Families of Carbon

Acids and Bases

Nomenclature and Conformations of Alkanes and Cycloalkanes

Stereochemistry

Nucleophilic Reactions

Alkenes and Alkynes I

Alkenes and Alkynes II

Nuclear Magnetic Resonance and Mass Spectrometry

Radical Reactions

Alcohols and Ethers

Alcohols From Carbonyl Compounds

Conjugated Unsaturated Systems

Reactions of Aromatic Compounds

Aldehydes and Ketones

Carboxylic Acids and Their Derivatives

Reactions at the Α Carbon of Carbonyl Compounds

Condensation and Conjugate Addition Reactions of Carbonyl Compounds

Amines

Transition Metal Complexes

Carbohydrates

Lipids

Amino Acids and Proteins

Nucleic Acids and Protein Synthesis

Filters

How many resonances would be expected in the broadband proton-decoupled ¹³C spectrum of:

How many resonances would be expected in the broadband proton-decoupled ¹³C spectrum of:

Which isomer of C₇H₇Cl exhibits strong IR absorbances at 690 and 750 cm^-¹?

Recalling that benzene has a resonance energy of 152 kJ mol^-1 and naphthalene has a resonance energy of 255 kJ mol^-1,predict the positions which would be occupied by bromine when phenanthrene (below)undergoes addition of Br₂.