Free Benzene and Aromatic Compounds MCQs with Answers
172 Benzene and Aromatic Compounds MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Benzene has a planar ring of delocalised π electrons, giving aromatic stability and equal carbon-carbon bond lengths. The topic covers resonance, electrophilic substitution reactions such as nitration, halogenation, sulphonation and Friedel-Crafts reactions, along with substituent effects and the distinction between substitution in benzene and addition in ordinary alkenes.
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172 questions · page 4 of 9
- A. More π-bonds
- B. Localized π-electrons
- C. Delocalized π-electrons
- D. More σ-bonds
Explanation: It undergoes resonance via π electron delocalization. Thus, the presence of 3 π bonds makes it less reactive and more stable than ethene…
Correct answer: Delocalized π-electrons- A. -OH
- B. -OCH3
- C. -CHO
- D. -NH2
Explanation: OH and - NHCOCH 3 are ortho and para directing groups. These are also the electron donating groups and the attack of the incoming groups…
Correct answer: -OH- A. Phenol
- B. Benzene
- C. Nitrobenzene
- D. Chlorobenzene
Explanation: Sulphonation of phenol at high temperature gives predominantly para isomer i.e. 4-phenol sulphonic acid.
Correct answer: Phenol- A. 3
- B. 4
- C. 5
- D. 6
Explanation: In Kekule's structure, the carbon atoms in benzene are arranged in a hexagonal ring with each carbon atom is attached to two other carbon…
Correct answer: 5- A. Paraffins
- B. Alkene
- C. Benzene
- D. Cyclohexane
Explanation: In the International Union of Pure and Applied Chemistry (IUPAC) system, aromatic hydrocarbons such as those above are named as…
Correct answer: Benzene- A. Atomic orbital treatment of benzene
- B. Resonance method
- C. Both (a) and (b)
- D. None
Explanation: By virtue of resonance, the benzene molecule is stabilized; the pi electrons are delocalized around the ring structure.
Correct answer: Both (a) and (b)- A. Isomerization
- B. Aromatization
- C. Dealkylation
- D. Rearrangement
Explanation: Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor.
Correct answer: Aromatization- A. A
- B. B
- C. C
- D. D
Explanation: The benzyl free radical has the formula C 6H 5CH 2•. The benzyl cation or phenylcarbenium ion is the carbocation with formula C 6H 5CH+2…
Correct answer: C- A. dil. NaOH
- B. dil. HNO3
- C. Conc. HNO3
- D. Acidified KMnO4
Explanation: Toluene should be heated in presence of acidified \[KMn{O_4}\] to carry out oxidation of Toluene.
Correct answer: Acidified KMnO4- A. Dewar
- B. Faraday
- C. Down
- D. Kekule
Explanation: German chemist August Kekulé visualized the ring structure of benzene in 1865.
Correct answer: Kekule- A. Three double bonds
- B. Two double bonds
- C. One double bond
- D. Delocalized π-electron charge
Explanation: Benzene is an organic chemical compound with the molecular formula C6H6.
Correct answer: Delocalized π-electron charge- A. Normal series of paraffins
- B. Alkene
- C. Benzene
- D. Cyclohexane
Explanation: In the International Union of Pure and Applied Chemistry (IUPAC) system, aromatic hydrocarbons such as those above are named as…
Correct answer: Benzene- A. AlCl3
- B. HNO3
- C. BeCl2
- D. NaCl
Explanation: Aluminium trichloride (AlCl3) is often used as a catalyst in Friedel-Crafts reactions since it acts as a Lewis acid and coordinates with…
Correct answer: AlCl3- A. Substitution reactions
- B. Addition reactions
- C. Oxidation reactions
- D. Elimination reactions
Explanation: Due to presence of pi-bonds benzene can not under go elimination reaction.
Correct answer: Elimination reactions- A. Toluene
- B. Benzene
- C. Nitrobenzene
- D. Chlorobenzene
Explanation: A process for the sulphonation of toluene in the liquid phase to produce a product comprising chiefly p-toluene sulphonic acid which…
Correct answer: Toluene- A. Benzene
- B. Ethene
- C. Ethane
- D. Ethyne
Explanation: The π bond in ethene is weak compared to the sigma bond between the two carbons.
Correct answer: Ethene- A. They have high percentage of hydrogen
- B. They have a ring structure
- C. They have high percentage of carbon
- D. They resist reaction with air
Explanation: The aromatic compound displays aromaticity. They burn with a strong sooty yellow flame.
Correct answer: They have high percentage of carbon- A. Isomerization
- B. Aromatization
- C. Dealkylation
- D. Rearrangement
Explanation: Aromatization is a chemical reaction in which an aromatic system is formed from a single nonaromatic precursor.
Correct answer: Aromatization- A. -NH2
- B. -OCH3
- C. -SO3H
- D. -OH
Explanation: -SO3H is correct because the sulfonic acid group is meta-directing in electrophilic substitution reactions of monosubstituted benzene due…
Correct answer: -SO3H- A. Toluene
- B. Xylene
- C. Benzoic acid.
- D. Acetophenone
Explanation: The introduction of an alkyl group in the benzene ring in the presence of an alkyl halide and a catalyst AICI3 is called Friedel-Crafts…
Correct answer: Benzoic acid.