Benzenols,Phenols

Question 1

Question and Options

Answer 1

Answer and Explanation

Question 2

Which of the following is NOT an aromatic hydrocarbon? a) Benzene b) Toluene c) Cyclohexane d) Naphthalene

Answer 2

c) Cyclohexane. Cyclohexane is a saturated hydrocarbon and does not possess aromaticity.

Question 3

The IUPAC name for C6H5OH is: a) Phenol b) Benzyl alcohol c) Cyclohexanol d) Ethanol

Answer 3

a) Phenol. C6H5OH is known as phenol, a hydroxyl group (-OH) attached to a benzene ring.

Question 4

What is the general formula for alkanes and cycloalkanes(ringed shaped aromatic hydrocarbon)? a) CnH2n+2 b) CnH2n c) CnH2n-6 d) CnH2n-4

Answer 4

b) CnH2n. This is the general formula for alkanes.

Question 5

What is the hybridization of the carbon atoms in a benzene ring? a) sp b) sp2 c) sp3 d) sp3d

Answer 5

b) sp2. The carbon atoms in benzene are sp2 hybridized, forming a planar structure.

Question 6

Which of the following describes the bonding in a benzene ring? a) All single bonds b) All double bonds c) Alternating single and double bonds d) Delocalized pi electrons

Answer 6

d) Delocalized pi electrons. Benzene has delocalized pi electrons, contributing to its stability.

Question 7

What is the main difference between benzene and cyclohexane? a) The number of carbon atoms b) The presence of a double bond c) The presence of a ring structure d) The delocalization of electrons

Answer 7

d) The delocalization of electrons. Benzene has delocalized pi electrons, while cyclohexane does not.

Question 8

Which of the following is a characteristic of aromatic compounds? a) They are highly reactive b) They undergo addition reactions easily c) They are planar and cyclic d) They have a strong, unpleasant odor

Answer 8

c) They are planar and cyclic. Aromatic compounds are characterized by their planar and cyclic structure.

Question 9

The term ‘ortho’ (o) in organic chemistry refers to: a) A substituent on the benzene ring at the 1,2 position b) A substituent on the benzene ring at the 1,3 position c) A substituent on the benzene ring at the 1,4 position d) A substituent on the benzene ring at the 1,5 position

Answer 9

a) A substituent on the benzene ring at the 1,2 position. ‘Ortho’ indicates adjacent substituents.

Question 10

What is the main product formed when benzene reacts with bromine in the presence of a catalyst? a) Bromobenzene b) Benzoic acid c) Cyclohexane d) Toluene

Answer 10

a) Bromobenzene. The reaction yields bromobenzene via electrophilic aromatic substitution.

Question 11

Which of the following is a common electrophilic aromatic substitution reaction? a) Friedel-Crafts alkylation b) SN1 reaction c) SN2 reaction d) Elimination reaction

Answer 11

a) Friedel-Crafts alkylation. This reaction introduces an alkyl group onto the aromatic ring.

Question 12

How does the presence of an electron-withdrawing group on the benzene ring affect its reactivity towards electrophilic attack? a) It increases reactivity b) It decreases reactivity c) It has no effect d) It depends on the specific group

Answer 12

b) It decreases reactivity. Electron-withdrawing groups reduce the electron density of the ring, making it less reactive.

Question 13

What is the major product formed when phenol reacts with concentrated nitric acid? a) Nitrophenol b) Picric acid c) Benzoic acid d) Benzene

Answer 13

a) Nitrophenol. The reaction leads to the nitration of phenol.

Question 14

Which of the following is a common method used for the preparation of phenols? a) Reduction of ketones b) Hydrolysis of aryl halides c) Oxidation of alcohols d) All of the above

Answer 14

d) All of the above. All methods can be used to prepare phenols.

Question 15

What is the main difference between 1-naphthol and 2-naphthol? a) The number of carbon atoms in the naphthalene ring b) The position of the hydroxyl group on the naphthalene ring c) The type of functional group attached to the naphthalene ring d) The presence of a double bond in the naphthalene ring

Answer 15

b) The position of the hydroxyl group on the naphthalene ring. 1-naphthol has -OH at position 1, while 2-naphthol has it at position 2.

Question 16

Which of the following compounds is NOT an isomer of toluene? a) o-xylene b) m-xylene c) p-xylene d) ethylbenzene

Answer 16

d) ethylbenzene. Ethylbenzene has a different structure compared to toluene and its isomers.

Question 17

What is the name of the compound formed when a methyl group is attached to the benzene ring at the para position? a) o-methylbenzene b) m-methylbenzene c) p-methylbenzene d) toluene

Answer 17

c) p-methylbenzene. The compound is known as p-toluene.

Question 18

Which of the following compounds is a good example of an aromatic aldehyde? a) Benzaldehyde b) Acetophenone c) Phenol d) Benzoic acid

Answer 18

a) Benzaldehyde. Benzaldehyde is an aromatic compound containing an aldehyde functional group.

Question 19

What is the major product formed when benzene reacts with acetyl chloride in the presence of aluminum chloride? a) Toluene b) Acetophenone c) Cyclohexane d) Benzoic acid

Answer 19

b) Acetophenone. This reaction is an example of electrophilic aromatic substitution.

Question 20

Which of the following is NOT a characteristic of aromatic carboxylic acids? a) They are generally acidic b) They are readily decarboxylated c) They can be prepared by oxidation of aromatic aldehydes d) They are less reactive than aliphatic carboxylic acids

Answer 20

b) They are readily decarboxylated. Aromatic carboxylic acids are generally not readily decarboxylated.

Question 21

Which of the following is a common method used for the synthesis of aromatic amines? a) Reduction of nitro compounds b) Acylation of aromatic hydrocarbons c) Halogenation of aromatic hydrocarbons d) Reaction with Grignard reagents

Answer 21

a) Reduction of nitro compounds. This method is commonly used to synthesize aromatic amines.

Question 22

What is the name of the compound formed when benzene reacts with an alkyl halide in the presence of a Lewis acid catalyst? a) Alkylbenzene b) Aryl halide c) Alkane d) Alkene

Answer 22

a) Alkylbenzene. The product is an alkyl-substituted benzene.

Question 23

Which of the following compounds is NOT a good example of an aromatic heterocycle? a) Pyridine b) Furan c) Pyrrole d) Cyclohexane

Answer 23

d) Cyclohexane. Cyclohexane is not aromatic as it does not meet the criteria for aromaticity.

Question 24

Which of the following is a common application of aromatic compounds? a) Pharmaceuticals b) Dyes c) Plastics d) All of the above

Answer 24

d) All of the above. Aromatic compounds are widely used in various applications.

Question 25

Explain the concept of aromaticity in detail, including the criteria for a compound to be considered aromatic.

Answer 25

Aromaticity is a special type of stability exhibited by certain cyclic, planar, and conjugated molecules. The criteria for a compound to be aromatic are: 1. **Cyclic:** The molecule must have a closed ring structure. 2. **Planar:** All atoms in the ring must lie in the same plane. 3. **Conjugated:** The ring must have alternating single and double bonds, creating a continuous system of overlapping pi orbitals. 4. **Hückel's Rule:** The number of pi electrons in the ring must follow Hückel's rule, which states that it must be equal to 4n+2, where n is an integer.

Question 26

Describe the structure and bonding in benzene and explain why it is more stable than cyclohexatriene.

Answer 26

Benzene has a planar, cyclic structure with six carbon atoms and six hydrogen atoms. Each carbon atom is sp2 hybridized and forms three sigma bonds: two with adjacent carbons and one with a hydrogen atom. The remaining p orbital on each carbon atom overlaps with the p orbitals of its neighboring carbon atoms, forming a continuous ring of delocalized pi electrons. This delocalization makes the benzene ring highly stable compared to cyclohexatriene, which has localized double bonds.

Question 27

What is the difference between electrophilic aromatic substitution and nucleophilic aromatic substitution?

Answer 27

Electrophilic aromatic substitution (EAS) involves the attack of an electrophile on an aromatic ring, resulting in the replacement of a hydrogen atom by the electrophile. Nucleophilic aromatic substitution (NAS) involves the attack of a nucleophile on an aromatic ring, typically occurring when the ring is deactivated by electron-withdrawing groups.

Question 28

Explain how the presence of substituents on the benzene ring can influence its reactivity towards electrophilic aromatic substitution.

Answer 28

"The reactivity of a benzene ring towards electrophilic aromatic substitution can be influenced by substituents: Electron-donating groups increase reactivity by enhancing electron density,

Question 29

Question

Answer 29

Answer and Explanation

Question 30

Describe the mechanism of Friedel-Crafts alkylation and explain the role of the Lewis acid catalyst.

Answer 30

Friedel-Crafts alkylation is an electrophilic aromatic substitution reaction where an alkyl group is attached to a benzene ring. The reaction requires a Lewis acid catalyst, typically aluminum chloride (AlCl3).\n\n**Mechanism:**\n1. **Formation of the electrophile:** The Lewis acid catalyst reacts with the alkyl halide to generate a carbocation, which acts as the electrophile.\n2. **Attack by the benzene ring:** The electrophilic carbocation attacks the electron-rich benzene ring, forming a sigma complex (an intermediate).\n3. **Loss of a proton:** A proton is removed from the sigma complex, restoring the aromaticity of the benzene ring.\n\nThe Lewis acid catalyst plays a crucial role by:\n• **Activating the alkyl halide:** It polarizes the carbon-halogen bond, making the alkyl group more electrophilic.\n• **Stabilizing the carbocation:** It helps to stabilize the carbocation intermediate, making it more reactive.

Question 31

Explain how the position of the substituent in a substituted benzene ring can affect its physical and chemical properties.

Answer 31

The position of a substituent on a benzene ring can have a significant impact on the compound's physical and chemical properties. This is because substituents can influence electron density distribution in the ring, affecting its reactivity and polarity.\n• **Ortho, meta, and para isomers:** Isomers with substituents at different positions (ortho, meta, and para) can exhibit different melting points, boiling points, dipole moments, solubilities, and reactivities.\n• **Effect on reactivity:** Electron-donating groups can increase the reactivity of the benzene ring, while electron-withdrawing groups can decrease it.\n• **Effect on polarity:** Polar substituents can increase the polarity of the molecule, while non-polar substituents can decrease it.

Question 32

Describe the synthesis of phenol from benzene. Explain the mechanism of the reaction and the role of the catalyst.

Answer 32

Phenol can be synthesized from benzene through a two-step process involving the following reactions:\n\n**Step 1: Halogenation**\n• **Reaction:** Benzene reacts with bromine (Br2) in the presence of a catalyst (iron or iron(III) bromide) to produce bromobenzene.\n• **Mechanism:** The reaction involves the formation of a bromonium ion (Br+), which acts as an electrophile, and attacks the benzene ring. The catalyst helps to generate the electrophile and facilitate the reaction.\n\n**Step 2: Hydrolysis**\n• **Reaction:** Bromobenzene is then treated with a strong base (like NaOH) at high temperature and pressure to yield phenol.\n• **Mechanism:** The reaction proceeds through a nucleophilic aromatic substitution mechanism. The hydroxide ion acts as a nucleophile, attacking the bromobenzene ring, leading to the formation of phenol and sodium bromide.

Question 33

What are the main differences between aliphatic and aromatic hydrocarbons?

Answer 33

Aliphatic and aromatic hydrocarbons are two distinct classes of organic compounds.\n\n**Aliphatic hydrocarbons:**\n• **Structure:** Chain-like or branched structures, with single, double, or triple bonds.\n• **Reactivity:** Generally more reactive than aromatics. They readily undergo addition reactions.\n• **Stability:** Less stable than aromatics.\n• **Examples:** Alkanes, alkenes, alkynes.\n\n**Aromatic hydrocarbons:**\n• **Structure:** Contain a benzene ring or other cyclic structures with delocalized pi electrons.\n• **Reactivity:** Less reactive than aliphatics. They tend to undergo substitution reactions.\n• **Stability:** More stable than aliphatics due to the delocalization of pi electrons.\n• **Examples:** Benzene, toluene, phenol.

Question 34

Discuss the importance of aromatic hydrocarbons in everyday life, giving examples.

Answer 34

Aromatic hydrocarbons are essential compounds in a wide range of applications, playing a vital role in various aspects of our daily lives.\n• **Medicine:** Many pharmaceuticals and medicinal compounds are based on aromatic structures.\n• **Agriculture:** Aromatic compounds are used in pesticides and herbicides to control pests and weeds.\n• **Dyes and Pigments:** Aromatic compounds form the basis of many colorful dyes and pigments used in textiles, paints, and inks.\n• **Plastics and Polymers:** Aromatic hydrocarbons are used in the production of a variety of plastics and synthetic polymers.\n• **Fuels:** Petroleum, which contains aromatic hydrocarbons, is a major source of fuel.\n• **Food:** Aromatic compounds are used as flavoring agents in food and beverages.\n• **Fragrances and Perfumes:** Many fragrances and perfumes contain aromatic compounds.

Question 35

What are some of the health risks associated with exposure to aromatic hydrocarbons?

Answer 35

Aromatic hydrocarbons can pose various health risks, especially when exposed to them in high concentrations or over prolonged periods.\n• **Cancer:** Some aromatic compounds, particularly polycyclic aromatic hydrocarbons (PAHs) found in coal tar and cigarette smoke, are known carcinogens (cancer-causing agents).\n• **Respiratory problems:** Exposure to certain aromatic hydrocarbons can irritate the respiratory system, leading to coughing, wheezing, and difficulty breathing.\n• **Skin irritation:** Some aromatic hydrocarbons can cause skin irritation, rashes, and dermatitis.\n• **Neurotoxicity:** Certain aromatic hydrocarbons can affect the nervous system, leading to headaches, dizziness, and neurological disorders.\n• **Reproductive effects:** Some aromatic hydrocarbons can disrupt hormone function and affect fertility.

Question 36

Explain how the electrophilic aromatic substitution reaction can be used to synthesize various aromatic compounds.

Answer 36

Electrophilic aromatic substitution (EAS) is a powerful tool for synthesizing a wide variety of aromatic compounds. The reaction involves the replacement of a hydrogen atom on a benzene ring with an electrophile.\n\n**Examples of EAS reactions for synthesis:**\n• **Friedel-Crafts Alkylation:** Alkylating a benzene ring with an alkyl halide in the presence of a Lewis acid catalyst.\n• **Friedel-Crafts Acylation:** Acylating a benzene ring with an acyl chloride or anhydride in the presence of a Lewis acid catalyst.\n• **Nitration:** Introducing a nitro group (-NO2) to the benzene ring using a mixture of concentrated nitric acid and sulfuric acid.\n• **Halogenation:** Introducing a halogen (bromine or chlorine) to the benzene ring using a halogenating agent like bromine or chlorine in the presence of a catalyst.\n• **Sulfonation:** Introducing a sulfonic acid group (-SO3H) to the benzene ring using concentrated sulfuric acid.

Question 37

What are the challenges associated with the synthesis of aromatic compounds, and how are these challenges addressed?

Answer 37

Synthesizing aromatic compounds can be challenging due to the unique properties of the aromatic ring and the need to control reaction conditions.\n\n**Challenges:**\n• **Reactivity:** The relatively low reactivity of the benzene ring requires specific conditions and catalysts to induce substitution reactions.\n• **Regioselectivity:** Controlling the position of substituents in the ring is crucial.\n• **Side Reactions:** Aromatic compounds can undergo multiple reactions, leading to unwanted byproducts.\n\n**Addressing the Challenges:**\n• **Catalysts:** Using appropriate catalysts to enhance the reaction rate and selectivity.\n• **Control of Reaction Conditions:** Adjusting temperature, pressure, and concentrations to minimize side reactions.

Question 38

Explain how aromatic compounds contribute to the pharmaceutical industry, providing examples of drugs with aromatic structures.

Answer 38

Aromatic compounds are ubiquitous in the pharmaceutical industry. Their unique properties, including their ability to interact with biological targets, have made them essential building blocks for a wide range of drugs.\n\n**Examples of drugs with aromatic structures:**\n• **Aspirin (acetylsalicylic acid):** A common pain reliever and anti-inflammatory drug containing a benzene ring with a carboxylic acid group.\n• **Ibuprofen (an anti-inflammatory drug):** Contains a benzene ring with a propionic acid group.\n• **Paracetamol (acetaminophen):** A common analgesic and antipyretic containing a benzene ring with an amide group.\n• **Amoxicillin (an antibiotic):** Contains a benzene ring with a beta-lactam ring, a critical component for its antibiotic activity.\n• **Sulfa drugs (antibiotics):** A group of antibiotics containing a benzene ring with a sulfonamide group.

Question 39

Discuss the environmental impact of aromatic hydrocarbons.

Answer 39

"Aromatic hydrocarbons can have both positive and negative impacts on the environment.\n\n**Positive Impacts:**\n• **Biofuels:** Some aromatic hydrocarbons are used in biofuels, contributing to renewable energy sources.\n• **Polymers and Materials:** Aromatic compounds are used in the production of plastics and synthetic materials, which can contribute to durability and longevity of products.\n\n**Negative Impacts:**\n• **Pollution:** Emissions from combustion of fossil fuels release aromatic hydrocarbons into the air, leading to air pollution and contributing to health problems.\n• **Toxicity:** Certain aromatic compounds are toxic to aquatic life and can contaminate water sources.\n• **Persistence:** Many aromatic compounds persist in the environment, taking a long time to break down,

Question 40

Question and Options

Answer 40

Answer and Explanation

Question 41

1. Which of the following is NOT a characteristic of aromatic hydrocarbons? a) They are cyclic. b) They are planar. c) They have alternating double and single bonds. d) They are highly reactive.

Answer 41

Answer: d) They are highly reactive. Explanation: Aromatic hydrocarbons are generally less reactive than aliphatic hydrocarbons due to their stability conferred by aromaticity.

Question 42

2. What is the hybridization of the carbon atoms in benzene? a) sp b) sp2 c) sp3 d) sp3d

Answer 42

Answer: b) sp2 Explanation: Each carbon atom in benzene forms three sigma bonds (one with another carbon and two with hydrogen atoms) and one pi bond. This requires sp2 hybridization.

Question 43

3. Which of the following is the most stable carbocation? a) Primary b) Secondary c) Tertiary d) Benzylic

Answer 43

Answer: d) Benzylic Explanation: Benzylic carbocations are stabilized by resonance with the aromatic ring, making them more stable than primary, secondary, or even tertiary carbocations.

Question 44

4. What is the major product of the reaction of benzene with nitric acid in the presence of sulfuric acid? a) Nitrobenzene b) Phenol c) Benzaldehyde d) Benzoic acid

Answer 44

Answer: a) Nitrobenzene Explanation: This reaction is a classic electrophilic aromatic substitution, where the electrophile (NO2+) attacks the benzene ring to form nitrobenzene.

Question 45

5. Which of the following reactions is NOT a characteristic of benzene? a) Electrophilic Aromatic Substitution b) Nucleophilic Aromatic Substitution c) Addition reaction d) Friedel-Crafts alkylation

Answer 45

Answer: c) Addition reaction Explanation: Benzene's aromaticity makes it resistant to addition reactions. It prefers electrophilic aromatic substitution reactions which maintain its aromatic character.

Question 46

6. Which of the following compounds is an example of a polycyclic aromatic hydrocarbon? a) Toluene b) Naphthalene c) Phenol d) Benzoic acid

Answer 46

Answer: b) Naphthalene Explanation: Naphthalene consists of two fused benzene rings, making it a polycyclic aromatic hydrocarbon.

Question 47

7. What is the common name for the compound with the formula C6H5OH? a) Benzene b) Toluene c) Phenol d) Benzoic acid

Answer 47

Answer: c) Phenol Explanation: Phenol is a common name for the hydroxyl derivative of benzene.

Question 48

8. Which of the following is the correct IUPAC name for the compound with the formula C6H5COOH? a) Benzoic acid b) Phenol c) Toluene d) Benzene

Answer 48

Answer: a) Benzoic acid Explanation: Benzoic acid is the carboxylic acid derivative of benzene.

Question 49

9. Which of the following reactions is used to prepare benzoic acid from toluene? a) Friedel-Crafts acylation b) Oxidation c) Reduction d) Halogenation

Answer 49

Answer: b) Oxidation Explanation: Toluene can be oxidized to benzoic acid using oxidizing agents like potassium permanganate (KMnO4) or chromic acid (H2CrO4).

Question 50

10. Which of the following compounds is a good example of a phenol derivative? a) Acetaminophen b) Aspirin c) Salicylic acid d) All of the above

Answer 50

Answer: d) All of the above Explanation: All three compounds are derivatives of phenol, having a phenolic hydroxyl group attached to a benzene ring.

Question 51

1. Which of the following is NOT a characteristic of aromatic hydrocarbons?a) They are cyclic.b) They are planar.c) They have alternating double and single bonds.d) They are highly reactive.

Answer 51

Answer: d) They are highly reactive.Explanation: Aromatic hydrocarbons are generally less reactive than aliphatic hydrocarbons due to their stability conferred by aromaticity.

Question 52

2. What is the hybridization of the carbon atoms in benzene?a) spb) sp2c) sp3d) sp3d

Answer 52

Answer: b) sp2Explanation: Each carbon atom in benzene forms three sigma bonds (one with another carbon and two with hydrogen atoms) and one pi bond. This requires sp2 hybridization.

Question 53

3. Which of the following is the most stable carbocation?a) Primaryb) Secondaryc) Tertiaryd) Benzylic

Answer 53

Answer: d) BenzylicExplanation: Benzylic carbocations are stabilized by resonance with the aromatic ring

Question 54

4. What is the major product of the reaction of benzene with nitric acid in the presence of sulfuric acid?a) Nitrobenzeneb) Phenolc) Benzaldehyded) Benzoic acid

Answer 54

Answer: a) NitrobenzeneExplanation: This reaction is a classic electrophilic aromatic substitution

Question 55

5. Which of the following reactions is NOT a characteristic of benzene? a) Electrophilic Aromatic Substitutionb) Nucleophilic Aromatic Substitutionc) Addition reactiond) Friedel-Crafts alkylation

Answer 55

Answer: c) Addition reactionExplanation: Benzene's aromaticity makes it resistant to addition reactions. It prefers electrophilic aromatic substitution reactions which maintain its aromatic character.

Question 56

6. Which of the following compounds is an example of a polycyclic aromatic hydrocarbon?a) Tolueneb) Naphthalenec) Phenold) Benzoic acid

Answer 56

Answer: b) NaphthaleneExplanation: Naphthalene consists of two fused benzene rings

Question 57

7. What is the common name for the compound with the formula C6H5OH?a) Benzeneb) Toluenec) Phenold) Benzoic acid

Answer 57

Answer: c) PhenolExplanation: Phenol is a common name for the hydroxyl derivative of benzene.

Question 58

8. Which of the following is the correct IUPAC name for the compound with the formula C6H5COOH?a) Benzoic acidb) Phenolc) Toluened) Benzene

Answer 58

Answer: a) Benzoic acidExplanation: Benzoic acid is the carboxylic acid derivative of benzene.

Question 59

9. Which of the following reactions is used to prepare benzoic acid from toluene?a) Friedel-Crafts acylationb) Oxidationc) Reductiond) Halogenation

Answer 59

Answer: b) OxidationExplanation: Toluene can be oxidized to benzoic acid using oxidizing agents like potassium permanganate (KMnO4) or chromic acid (H2CrO4).

Question 60

10. Which of the following compounds is a good example of a phenol derivativea) Acetaminophenb) Aspirinc) Salicylic acidd) All of the above

Answer 60

Answer: d) All of the aboveExplanation: All three compounds are derivatives of phenol

Question 61

11. Which of the following statements is TRUE about the acidity of phenols?a) Phenols are more acidic than alcohols.b) Phenols are less acidic than alcohols.c) Phenols have the same acidity as alcohols.d) The acidity of phenols depends on the substituents present.

Answer 61

Answer: a) Phenols are more acidic than alcohols.Explanation: The resonance stabilization of the phenoxide ion makes phenols more acidic than alcohols.

Question 62

12. What is the major product of the reaction of phenol with bromine in the presence of iron (III) bromide?a) 2

Answer 62

4

Question 63

13. Which of the following is NOT a characteristic of aromatic amines?a) They are weak bases.b) They are readily oxidized.c) They are good nucleophiles.d) They are less reactive than aliphatic amines.

Answer 63

Answer: d) They are less reactive than aliphatic amines.Explanation: Aromatic amines are more reactive than aliphatic amines due to the electron-donating effect of the amino group. This makes them more susceptible to electrophilic attack.

Question 64

14. What is the name of the reaction used to convert nitrobenzene to anilinea) Friedel-Crafts alkylationb) Reductionc) Oxidationd) Halogenation

Answer 64

Answer: b) ReductionExplanation: The nitro group in nitrobenzene is reduced to an amino group to form aniline. This can be achieved using reducing agents like tin and hydrochloric acid.

Question 65

15. Which of the following is the correct IUPAC name for the compound with the formula C6H5NH2?a) Phenylamineb) Benzylaminec) Anilined) Aminobenzene

Answer 65

Answer: c) AnilineExplanation: Aniline is the common name for the simplest aromatic amine.

Question 66

16. Which of the following compounds is a good example of a diazonium salt?a) Benzenediazonium chlorideb) Nitrobenzenec) Phenold) Aniline

Answer 66

Answer: a) Benzenediazonium chlorideExplanation: Diazonium salts are formed from aromatic amines by reaction with nitrous acid. Benzenediazonium chloride is a classic example.

Question 67

17. What is the major product of the reaction of benzene with diazonium salts?a) Nitrobenzeneb) Phenolc) Azobenzened) Aniline

Answer 67

Answer: c) AzobenzeneExplanation: This reaction is known as azo coupling

Question 68

18. Which of the following is a common use of diazonium salts in organic synthesis?a) Preparation of azo dyesb) Preparation of nitro compoundsc) Preparation of aldehydesd) Preparation of ketones

Answer 68

Answer: a) Preparation of azo dyesExplanation: Diazonium salts are important intermediates in the synthesis of azo dyes. The azo group (-N=N-) is responsible for the vibrant colors of these dyes.

Question 69

19. What is the major product of the reaction of benzene with benzoyl chloride in the presence of aluminum chloride?a) Benzophenoneb) Benzaldehydec) Benzoic acidd) Toluene

Answer 69

Answer: a) BenzophenoneExplanation: This reaction is a Friedel-Crafts acylation

Question 70

20. Which of the following reactions is an example of an electrophilic aromatic substitution reaction?a) Friedel-Crafts alkylationb) Halogenationc) Nitrationd) All of the above

Answer 70

Answer: d) All of the aboveExplanation: All these reactions involve the attack of an electrophile on the benzene ring

Question 71

21. What is the purpose of the catalyst in the Friedel-Crafts acylation reaction?a) To increase the rate of the reactionb) To decrease the rate of the reactionc) To act as a Lewis acidd) To act as a Lewis base

Answer 71

Answer: c) To act as a Lewis acidExplanation: Aluminum chloride (AlCl3) is a common catalyst in Friedel-Crafts acylation. It acts as a Lewis acid to activate the acyl chloride and generate the electrophile for the reaction.

Question 72

22. Which of the following compounds is a good example of a heterocyclic aromatic compounda) Pyridineb) Furanc) Thiophened) All of the above

Answer 72

Answer: d) All of the aboveExplanation: All three compounds are heterocyclic aromatic compounds. They contain at