Question 1

List the criteria which compounds must meet in order to be considered aromatic.

Accepted Answer

1. The structure must be cyclic.
2. Each atom in the ring must have an unhybridized p orbital.
3. The structure must be planar or nearly planar so that overlap of these p orbitals is effective.
4. The π network must contain 4n + 2 electrons (where n is a whole number), so that delocalization of the π electrons results in a lowering of the molecule's electronic energy.

Question 2

What is the bond order of the carbon-carbon bonds in benzene?

Accepted Answer

A)  0.5 
B)  1 
C)  1.5 
D)  2 
E)  3 
A)  0.5 
B)  1 
C)  1.5 
D)  2 
E)  3 C

Question 3

Explain the relative acidities of cyclohexene (pKa of 46) and cyclopentadiene (pKa of 16).

Accepted Answer

The conjugate base of cyclopentadiene is aromatic.

Question 4

Provide the structure of o-bromostyrene.

Accepted Answer

The answer of Provide the structure of o-bromostyrene....

Question 5

What compound results when cyclooctatetraene is treated with excess potassium metal?

Accepted Answer

dipotassiu

Question 6

Classify cyclopropenyl cation as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network

Accepted Answer

The answer of Classify cyclopropenyl cation as aromatic, antiaromatic, or...

Question 7

Rank the following in order of increasing pKa (from lowest to highest pKa)

Accepted Answer

A)  1 < 2 < 3 
B)  3 < 2 < 1 
C)  2 < 1 < 3 
D)  3 < 1 < 2 
E)  2 < 3 < 1 
A)  1 < 2 < 3 
B)  3 < 2 < 1 
C)  2 < 1 < 3 
D)  3 < 1 < 2 
E)  2 < 3 < 1

Question 8

Classify pyridine as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Accepted Answer

The answer of Classify pyridine as aromatic, antiaromatic, or nonaromatic....

Question 9

Which of the following is not a fused-ring heterocycle?

Accepted Answer

A)  purine 
B)  pyrimidine 
C)  benzofuran 
D)  indole 
E)  quinoline 
A)  purine 
B)  pyrimidine 
C)  benzofuran 
D)  indole 
E)  quinoline

Question 10

Name two of the three common allotropes of carbon.

Accepted Answer

diamond; graphite; f

Question 11

Which of the following structures, if flat, would be classified as antiaromatic?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E)

Question 12

Is the all-cis form of [10]annulene aromatic? Explain.

Accepted Answer

No. Planarity, which

Question 13

Provide an acceptable name for the compound below.

Accepted Answer

ortho-xyle

Question 14

Classify the compound below as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Accepted Answer

The answer of Classify the compound below as aromatic, antiaromatic,...

Question 15

When cycloheptatriene is deprotonated, an anion with seven resonance forms of equal energy can be drawn. Given this fact, explain why cycloheptatriene is only slightly more acidic than propene.

Accepted Answer

Each resonance form

Question 16

Classify the compound below as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Accepted Answer

The answer of Classify the compound below as aromatic, antiaromatic,...

Question 17

Provide the structure of m-xylene.

Accepted Answer

The answer of Provide the structure of m-xylene....

Question 18

Provide the structure of 2,4,6-trichlorophenol.

Accepted Answer

The answer of Provide the structure of 2,4,6-trichlorophenol....

Question 19

Classify the compound below as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Accepted Answer

The answer of Classify the compound below as aromatic, antiaromatic,...

Question 20

Is cyclooctatetraene a planar molecule? Explain.

Accepted Answer

No. In addition to increasing

Exam 16: Aromatic Compounds

List the criteria which compounds must meet in order to be considered aromatic.

What is the bond order of the carbon-carbon bonds in benzene?

Explain the relative acidities of cyclohexene (pKa of 46) and cyclopentadiene (pKa of 16).

Provide the structure of o-bromostyrene.

What compound results when cyclooctatetraene is treated with excess potassium metal?

Classify cyclopropenyl cation as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network

Rank the following in order of increasing pKa (from lowest to highest pKa)

Classify pyridine as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Which of the following is not a fused-ring heterocycle?

Name two of the three common allotropes of carbon.

Which of the following structures, if flat, would be classified as antiaromatic?

Is the all-cis form of [10]annulene aromatic? Explain.

Provide an acceptable name for the compound below.

Classify the compound below as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

When cycloheptatriene is deprotonated, an anion with seven resonance forms of equal energy can be drawn. Given this fact, explain why cycloheptatriene is only slightly more acidic than propene.

Classify the compound below as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Provide the structure of m-xylene.

Provide the structure of 2,4,6-trichlorophenol.

Classify the compound below as aromatic, antiaromatic, or nonaromatic. Assume planarity of the π network.

Is cyclooctatetraene a planar molecule? Explain.

Introduction and Review

Structure and Properties of Organic Molecules

Structure and Stereochemistry of Alkanes

The Study of Chemical Reactions

Stereochemistry

Alkyl Halides: Nucleophilic Substitution and Elimination

Structure and Synthesis of Alkenes

Reactions of Alkenes

Alkynes

Structure and Synthesis of Alcohols

Reactions of Alcohols

Infrared Spectroscopy and Mass Spectrometry

Nuclear Magnetic Resonance Spectroscopy

Ethers, Epoxides, and Thioethers

Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy

Reactions of Aromatic Compounds

Ketones and Aldehydes

Amines

Carboxylic Acids

Carboxylic Acid Derivatives

Condensations and Alpha Substitutions of Carboxyl Compounds

Carbohydrates and Nucleic Acids

Amino Acids, Peptides, and Proteins

Lipids

Synthetic Polymers

Filters

Explain the relative acidities of cyclohexene (pK_a of 46) and cyclopentadiene (pK_a of 16).