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 7 of 9
- A. Between the C-C bonds of benzene
- B. Above and below the carbon bonds
- C. In the form of cloud above and below the benzene ring
- D. None of these
Explanation: Benzene is a cyclic molecule in which all of the ring atoms are sp2-hybridized.
Correct answer: In the form of cloud above and below the benzene ring- A. Between the C-C bonds of benzene
- B. Above and below the carbon bonds
- C. In the form of a cloud above and below the benzene ring
- D. None of these options is correct
Explanation: All of the carbon atoms in the benzene rings are sp2-hybridized: the overlap of the sp2 orbitals around the ring produces a framework of…
Correct answer: In the form of a cloud above and below the benzene ring- A. Increase electron density at the ortho and para positions
- B. Decrease electron density at the ortho and para positions
- C. Make benzene less reactive
- D. Both Options B and C are correct
Explanation: The meta groups deactivate the ring, by the inductive effect, in the presence of an electronegative atom, that withdraws the electrons…
Correct answer: Both Options B and C are correct- A. Anthracene
- B. Naphthalene
- C. Phenol
- D. None of these options is correct
Explanation: All of these compounds contain a benzene ring, hence all are aromatic.
Correct answer: None of these options is correct- A. In alkynes to identify the position of the triple bond
- B. In arenes to identify the position of the first substitution
- C. In arenes to identify the position of the second substitution
- D. In all hydrocarbons to identify the position of the functional group
Explanation: The terms ortho, meta, and para are prefixes used in organic chemistry to indicate the position of non-hydrogen substituents on a…
Correct answer: In arenes to identify the position of the second substitution- A. Three triple bonds
- B. Two double bonds
- C. Three double bonds
- D. No multiband
Explanation: Option C is correct since benzene is a hydrocarbon composed of six carbons connected via a covalent bond, and exists in the form of a…
Correct answer: Three double bonds- A. The two isomers of benzene
- B. The isomers of arenes
- C. The two-resonance structure of benzene
- D. The two-resonance structure of phenols
Explanation: This option is correct because kekule structure represents the resonating structure of benzene according to which benzene has a ring…
Correct answer: The two-resonance structure of benzene- A. Two double bonds
- B. Delocalized pi-electron charge
- C. Three double bonds
- D. One sigma bond
Explanation: Benzene has a delocalized pi-electron system. Its alternative double bonds cause the ring to become delocalized and constitute the…
Correct answer: Delocalized pi-electron charge- A. Two Double Bonds
- B. Delocalized Pi-Electron Charge
- C. Three Double Bonds
- D. One Sigma Bond
Explanation: Benzene is a cyclic molecule in which all of the ring atoms are sp2-hybridized and contain double bonds.
Correct answer: Delocalized Pi-Electron Charge- A. Benzene
- B. Toluene
- C. Phenol
- D. Diphenylmethane
Explanation: Diphenylmethane is a synthetic compound manufactured by 'The Friedel-Craft Reaction' of benzyl chloride with benzene in the presence of…
Correct answer: Diphenylmethane- A. Ortho
- B. Meta
- C. Para
- D. None of these
Explanation: Disubstituted benzene rings can be named based on the relative positions of the substituents: the prefix para is used iif they are found…
Correct answer: Para- A. 154 pm
- B. 120 pm
- C. 134 pm
- D. 139 pm
Explanation: The C−C bond length in benzene is 139 pm. All C−C and C=C bond lengths are the same in benzene.
Correct answer: 139 pm- A. Alicyclic
- B. Aliphatic compounds
- C. Aromatic compounds
- D. Acyclic compounds
Explanation: Correct option is C. Aromatic compounds, also known as "mono- and polycyclic aromatic hydrocarbons", are organic compounds containing one…
Correct answer: Aromatic compounds- A. Three triple bonds
- B. Two double bonds
- C. Three double bonds
- D. No multiband
Explanation: Correct option is C. There are 3 double bonds in benzene. Six single bonds between Carbons and Hydrogens, three single bonds between six…
Correct answer: Three double bonds- A. -COOH
- B. -COR
- C. -CN
- D. -OH
Explanation: "-OH" group favors electrophilic attack ortho or para to the substituent while the other group of options doesn't hence the answer is D.
Correct answer: -OH- A. Aldol condensation
- B. Wolf kishner reaction
- C. Wittig reaction
- D. Friedel and craft reaction
Explanation: The reaction in which benzene is reacted with alkyl or acyl halide in the presence of AlCl3 is called Friedel-Craft reaction.
Correct answer: Friedel and craft reaction- A. It has low melting and low boiling points
- B. It has high melting and high boiling points
- C. It has low melting and high boiling points
- D. It has a high solubility in polar solvents
Explanation: Arenes are aromatic compounds (contain benzene rings). Hence, they only possess weak Vander Waal's forces as their intermolecular forces…
Correct answer: It has low melting and low boiling points- A. NO2-
- B. HNO2
- C. NO3-
- D. NO2+
Explanation: Explanation:During the nitration of benzene which is an electrophilic substitution reaction, the active nitrating agent is NO2+.
Correct answer: NO2+- A. Alkyl group
- B. Phenyl group
- C. Benzyl group
- D. Methyl group
Explanation: A is incorrect as alkyl group is formed when one hydrogen is removed from an alkane chain;not a benzene ring.B is correct as when one…
Correct answer: Phenyl group- A. Conc. HNO3 and conc. HCl
- B. Conc. HNO3 and conc. Acetic acid
- C. Conc. HNO3 and H3PO4
- D. Conc. HNO3 and conc. H2SO4
Explanation: A is incorrect as these reactants are not used in nitration.B is incorrect as these reactants are not used in nitration.C is incorrect as…
Correct answer: Conc. HNO3 and conc. H2SO4