Question 1

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

Accepted Answer

D

Question 2

How would you name the following?

Accepted Answer

A

Question 3

Which of the following would not be aromatic (i.e.,which would not be unusually stable)?

Accepted Answer

C

Question 4

Which of the following molecules would you predict to be aromatic?

Accepted Answer

To be considered aromatic, a compound must meet the following criteria:
1. It must be cyclic.
2. It must be planar.
3. It must be fully conjugated (all atoms in the ring must be sp2 hybridized and participate in delocalized pi-electron system).
4. It must have 4n+2 pi electrons, where n is any integer (known as Hückel's Rule).

Option B meets all of these criteria, as it has a cyclic structure with alternating double bonds, all carbons are sp2 hybridized, the molecule is planar, and has 8 pi electrons (4n+2 where n=1), thus making it aromatic. 
Option A does not have a cyclic structure or a conjugated pi system.
Option C has an sp3 hybridized carbon, breaking the conjugation of the pi system.
Option D has a non-planar structure, as indicated by the tetrahedral geometry of the central carbon.
Option E has extra carbons disrupting the conjugated pi system.

Question 5

What is the common name for the following compound?

Accepted Answer

The common name for the compound 11eab5f7_3da4_eea3_a628_f34e16101e51_TB6928_00 is anisole, which is also known as methoxybenzene. Toluene, aniline, phenol, and cresol are different compounds with different structures and properties.

Question 6

The best experimental proof of aromaticity is

Accepted Answer

NMR chemical shifts, especially those of hydrogen atoms in the aromatic ring, provide strong evidence for aromaticity due to the characteristic downfield shifts caused by the ring current effect in aromatic systems.

Question 7

Which of the following is not a resonance structure involved in electrophilic aromatic bromination?

Accepted Answer

The answer of Which of the following is not a...

Question 8

What would be the expected product of the following reactions?

Accepted Answer

The answer of What would be the expected product of...

Question 9

Which of the following would you expect to be aromatic?

Accepted Answer

The answer of Which of the following would you expect...

Question 10

Which of the following reactions of aromatics is reversible?

Accepted Answer

Sulfonation is a reversible reaction as it involves the addition of sulfuric acid (H2SO4) to the aromatic ring, and the removal of the -SO3H group can be accomplished by treatment with hot aqueous acid. The other reactions listed are irreversible as they involve the substitution of a functional group onto the aromatic ring.

Question 11

Which of the following reactions has an aromatic transition state with (4n + 2)electrons involved?

Accepted Answer

The answer of Which of the following reactions has an...

Question 12

What reagents are typically required to accomplish bromination of an aromatic ring?

Accepted Answer

Bromination of an aromatic ring typically requires a Lewis acid catalyst such as iron(III) bromide (FeBr3) to facilitate the reaction.

Question 13

How many mononitrated (on the aromatic ring)derivatives of meta-xylene (= 1,3-dimethylbenzene)are possible? (Don't worry about how they might be made or which would be the major product.)

Accepted Answer

Meta-xylene has two methyl groups located at the 1 and 3 positions on a benzene ring. Nitration can occur at the 2, 4, or 6 positions relative to one of the methyl groups, but because of the symmetry of the molecule, nitration at the 2 or 6 positions relative to one methyl group is equivalent to nitration at the 2 or 6 positions relative to the other methyl group. Therefore, there are three unique positions where nitration can occur, leading to three possible mononitrated derivatives.

Question 14

Which of the following would you expect to react fastest in an S_N1 reaction (consider the mechanism)?

Accepted Answer

The S_N1 reaction is a radical chain reaction, with the initiation step involving the homolysis of a bond to generate two radicals. In this case, the most likely initiation step involves breaking the weakest bond, which is the C-H bond in compound A. Therefore, compound A would be expected to react fastest in this reaction.

Question 15

What is/are the major product(s)in the following reaction?

Accepted Answer

The reaction involves the addition of HBr to a double bond, which forms an alkyl halide. The major product will be the one where the Br attaches to the carbon that has the most hydrogen atoms attached to it, which is known as the Markovnikov's rule. In this case, both A and C show the correct product, so the answer is D. Choice B is not correct because it shows the wrong product. Therefore, D is the best choice.

Question 16

Which would be the best systematic name of vanillan,the primary flavoring ingredient in vanilla?

Accepted Answer

The systematic name of vanillan is 4-hydroxy-3-methoxybenzaldehyde. This is because it contains a hydroxyl group (-OH) and a methoxy group (-OCH3) on the benzene ring, as well as an aldehyde group (-CHO) on the carbon next to the benzene ring. The other answer choices contain different combinations of functional groups or they have the functional groups in different positions on the benzene ring, making them incorrect systematic names for vanillan.

Question 17

The reagents listed below all react readily with alkenes.Which one can react (slowly)irreversibly with an aromatic ring?

Accepted Answer

ED) Sulfuric acid (H2SO4) can catalyze the electrophilic aromatic substitution, allowing an aromatic ring to react slowly and irreversibly with it under certain conditions.E) Hydrogen peroxide (H2O2) in the presence of a catalyst can also participate in electrophilic aromatic substitution, albeit more slowly, leading to the oxidation of the aromatic ring.

Question 18

One of the double bonds in phenanthrene,shown below,is much more reactive than the others.Which one is it?

Accepted Answer

The answer of One of the double bonds in phenanthrene,shown...

Question 19

Which of the following best describes the electronic nature of cyclooctatetraene?

Accepted Answer

The answer of Which of the following best describes the...

Question 20

What would be the product of the following reaction?

Accepted Answer

The answer of What would be the product of the...

Quiz 15: Benzene and Aromaticity: Electrophilic Aromatic Substitution

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

How would you name the following?

Which of the following would not be aromatic (i.e.,which would not be unusually stable) ?

Which of the following molecules would you predict to be aromatic?

What is the common name for the following compound?

The best experimental proof of aromaticity is

Which of the following is not a resonance structure involved in electrophilic aromatic bromination?

What would be the expected product of the following reactions?

Which of the following would you expect to be aromatic?

Which of the following reactions of aromatics is reversible?

Which of the following reactions has an aromatic transition state with (4n + 2) electrons involved?

What reagents are typically required to accomplish bromination of an aromatic ring?

How many mononitrated (on the aromatic ring) derivatives of meta-xylene (= 1,3-dimethylbenzene) are possible? (Don't worry about how they might be made or which would be the major product.)

Which of the following would you expect to react fastest in an S_N1 reaction (consider the mechanism) ?

What is/are the major product(s) in the following reaction?

Which would be the best systematic name of vanillan,the primary flavoring ingredient in vanilla?

The reagents listed below all react readily with alkenes.Which one can react (slowly) irreversibly with an aromatic ring?

One of the double bonds in phenanthrene,shown below,is much more reactive than the others.Which one is it?

What would be the product of the following reaction?

Quiz 15: Benzene and Aromaticity: Electrophilic Aromatic Substitution

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

How would you name the following?

Which of the following would not be aromatic (i.e.,which would not be unusually stable) ?

Which of the following molecules would you predict to be aromatic?

What is the common name for the following compound?

The best experimental proof of aromaticity is

Which of the following is not a resonance structure involved in electrophilic aromatic bromination?

What would be the expected product of the following reactions?

Which of the following would you expect to be aromatic?

Which of the following reactions of aromatics is reversible?

Which of the following reactions has an aromatic transition state with (4n + 2) electrons involved?

What reagents are typically required to accomplish bromination of an aromatic ring?

How many mononitrated (on the aromatic ring) derivatives of meta-xylene (= 1,3-dimethylbenzene) are possible? (Don't worry about how they might be made or which would be the major product.)

Which of the following would you expect to react fastest in an SN1 reaction (consider the mechanism) ?

What is/are the major product(s) in the following reaction?

Which would be the best systematic name of vanillan,the primary flavoring ingredient in vanilla?

The reagents listed below all react readily with alkenes.Which one can react (slowly) irreversibly with an aromatic ring?

One of the double bonds in phenanthrene,shown below,is much more reactive than the others.Which one is it?

Which of the following best describes the electronic nature of cyclooctatetraene?

What would be the product of the following reaction?

Which of the following would you expect to react fastest in an S_N1 reaction (consider the mechanism) ?