Aromatic Compounds: Structure, Properties, and Reactions

Question 1

Which of the following is a characteristic property of aromatic compounds?

Accepted Answer

They are planar and have a delocalized electron cloud.

Answer

They are highly reactive due to their high electron density.

Answer

They have low volatility due to their strong intermolecular forces.

Answer

They are soluble in water due to their polar nature.

Question 2

Which of the following compounds is the most reactive towards electrophilic aromatic substitution?

Accepted Answer

Toluene

Answer

Benzene

Answer

Chlorobenzene

Answer

Nitrobenzene

Question 3

Of the following compounds, which can undergo nucleophilic aromatic substitution reactions?

Accepted Answer

Aniline

Answer

Benzene

Answer

Nitrobenzene

Answer

Benzoic acid

Question 4

In the Friedel-Crafts acylation reaction, which reagent is used to introduce an acyl group into the aromatic ring?

Accepted Answer

Acetyl chloride

Answer

Sodium borohydride

Answer

Potassium permanganate

Answer

Silver nitrate

Question 5

What is the major product of the nitration of toluene?

Accepted Answer

2-Nitrotoluene

Answer

3-Nitrotoluene

Answer

4-Nitrotoluene

Answer

2,4-Dinitrotoluene

Question 6

What is the hybridization of the carbon atoms in the benzene ring?

Accepted Answer

sp2

Answer

sp

Answer

sp3

Answer

sp3d

Question 7

What is the IUPAC name of the compound with the molecular formula C6H5CH2CH3?

Accepted Answer

Ethylbenzene

Answer

Propylbenzene

Answer

Methylstyrene

Answer

Phenylpropane

Question 8

Which of the following is NOT a major use of aromatic compounds?

Accepted Answer

As food additives

Answer

As solvents

Answer

In the production of dyes

Answer

As starting materials for pharmaceuticals

Question 9

In a Friedel-Crafts reaction, what is the primary function of the Lewis acid catalyst?

Accepted Answer

To activate the electrophile

Answer

To activate the nucleophile

Answer

To form a complex with the product

Answer

To provide hydrogen ions

Question 10

Which of the following compounds is NOT aromatic?

Accepted Answer

Cyclohexane

Answer

Benzene

Answer

Naphthalene

Answer

Pyridine

Question 11

What is the mechanism of electrophilic aromatic substitution?

Accepted Answer

Electrophilic attack on the aromatic ring followed by protonation

Answer

Electrophilic addition to the aromatic ring followed by protonation

Answer

Nucleophilic addition to the aromatic ring followed by elimination

Answer

Radical addition to the aromatic ring followed by rearrangement

Question 12

Which of the following reagents is commonly used for nitration of aromatic compounds?

Accepted Answer

HNO3/H2SO4

Answer

HCl/AlCl3

Answer

KMnO4

Answer

NaOH/H2O

Question 13

What is the hybridization of the carbon atoms in the benzene ring?

Accepted Answer

sp2 with planar geometry

Answer

sp

Answer

sp3 with tetrahedral geometry

Answer

sp3d

Question 14

The carbon atoms in the benzene ring are hybridized as:

Accepted Answer

sp²

Answer

sp

Answer

sp³

Answer

sp³d

Question 15

Which of the following reactions is a characteristic property of aromatic compounds?

Accepted Answer

Electrophilic substitution

Answer

Electrophilic addition

Answer

Nucleophilic addition

Answer

Free radical substitution

Question 16

Which of the following properties is characteristic of aromatic compounds?

Accepted Answer

Planarity

Answer

Polar bonds

Answer

Low boiling point

Answer

High solubility in water

Question 17

Which of the following reactions is a characteristic of aromatic compounds?

Accepted Answer

Electrophilic aromatic substitution

Answer

Nucleophilic addition

Answer

Free radical addition

Answer

Diels-Alder reaction

Question 18

In the reaction between benzene and nitric acid in the presence of sulfuric acid, what is the major product?

Accepted Answer

Nitrobenzene

Answer

Phenol

Answer

Benzoic acid

Answer

Aniline

Question 19

Which of the following compounds is an example of a polycyclic aromatic hydrocarbon?

Accepted Answer

Naphthalene

Answer

Toluene

Answer

Ethylbenzene

Answer

Benzene

Question 20

What is the effect of resonance in aromatic compounds?

Accepted Answer

It enhances molecular stability.

Answer

It makes the molecule polar.

Answer

It increases molecular reactivity.

Question 21

Which of the following is a naturally occurring aromatic compound?

Accepted Answer

Quercetin

Answer

Ethylene

Answer

Acetylene

Question 22

What is the significance of aromatic compounds in biological systems?

Accepted Answer

They participate in essential metabolic pathways.

Answer

They are used as building blocks for polymers.

Answer

They are used as fuels for combustion engines.

Answer

They are employed as solvents in industrial processes.

Question 23

Which of the following compounds exhibits the characteristics of aromaticity?

Accepted Answer

Benzene

Answer

Cyclopropane

Answer

Ethene

Answer

Propane

Question 24

A characteristic reaction of aromatic compounds is:

Accepted Answer

Electrophilic aromatic substitution

Answer

Nucleophilic addition

Answer

Diels-Alder reaction

Answer

Free radical substitution

Question 25

Which of the following species is a common electrophile in electrophilic aromatic substitution reactions?

Accepted Answer

NO2+

Answer

Li+

Answer

H2O

Answer

Br-

Question 26

The product obtained from the Friedel-Crafts acylation of benzene with acetyl chloride is:

Accepted Answer

Acetophenone

Answer

Benzaldehyde

Answer

Benzyl alcohol

Answer

Benzoic acid

Question 27

An example of an aromatic heterocycle is:

Accepted Answer

Pyridine

Answer

Piperidine

Answer

Cyclohexane

Answer

Tetrahydrofuran

Question 28

The electrophilic addition of bromine to an aromatic compound proceeds through the formation of:

Accepted Answer

A bromonium ion

Answer

A free radical

Answer

A carbocation

Answer

A zwitterion

Question 29

The enhanced acidity of phenol compared to aliphatic alcohols can be primarily attributed to:

Accepted Answer

The resonance stabilization of its conjugate base

Answer

The inductive effect of the hydroxyl group

Answer

The steric hindrance of the hydroxyl group

Answer

The hydrogen bonding ability of the hydroxyl group

Question 30

Which of the following compounds fulfills the Hückel criteria for aromaticity?

Accepted Answer

Benzene

Answer

Ethylene

Answer

Propane

Answer

Cyclohexane

Question 31

What is the hybridization of the carbon atoms in the benzene ring?

Accepted Answer

sp²

Answer

sp

Answer

sp³

Question 32

Which of the following reactions is a characteristic electrophilic aromatic substitution (EAS) reaction?

Accepted Answer

Benzene + Br2 + FeBr3 → Bromobenzene

Answer

CH3COOH + NaOH → CH3COONa + H2O

Answer

CH2=CH2 + HBr → CH3CH2Br

Answer

CH3CH3 + Br2 → CH3CH2Br

Question 33

Which of the following alkenes has the highest boiling point?

Accepted Answer

CH3(CH2)7CH=CH2

Answer

CH3CH2CH=CHCH3

Answer

CH3CH=CHCH2CH3

Answer

(CH3)2C=CH2

Question 34

Which of the following reagents can be used to distinguish between terminal and internal alkenes?

Accepted Answer

KMnO4

Answer

HCl

Answer

H2O

Answer

NaOH

Question 35

What is the hybridization state of the carbon atoms within the benzene ring?

Accepted Answer

sp²

Answer

sp³d

Answer

sp

Answer

sp³

Question 36

Which of the following reactions is a characteristic reaction type for aromatic compounds?

Accepted Answer

Electrophilic aromatic substitution

Answer

Diels-Alder reaction

Answer

Radical addition

Answer

Nucleophilic addition

Question 37

Which of the following substituents is classified as an activating group in electrophilic aromatic substitution reactions?

Accepted Answer

-OCH₃

Answer

-CF₃

Answer

-Cl

Answer

-NO₂

Question 38

What is the reaction mechanism of the Friedel-Crafts acylation reaction?

Accepted Answer

Electrophilic aromatic substitution

Answer

SN1 reaction

Answer

Diels-Alder reaction

Answer

Nucleophilic addition

Question 39

What is the primary role of a catalyst in the hydrogenation of benzene?

Accepted Answer

To provide an alternative reaction pathway with lower activation energy

Answer

To remove the hydrogen gas produced

Answer

To increase the concentration of benzene

Question 40

Which of the following compounds was historically used as an anti-knock agent in gasoline?

Accepted Answer

Tetraethyllead

Answer

Toluene

Answer

Benzene

Answer

Xylene

Question 41

What is the IUPAC name for the compound commonly known as phenol?

Accepted Answer

Hydroxybenzene

Answer

Carbolic acid

Answer

Phenylol

Answer

Benzeneol