Free Chemistry of Hydrocarbons MCQs with Answers

• A. KMnO4
• B. K2Cr2O7
• C. KHMnO4
• D. V2O5

Explanation: Vanadium pentoxide (V2O5) can be used as an oxidizing agent to oxidize benzene and its derivatives under specific conditions.

• A. Two
• B. One
• C. Three
• D. None of these

Explanation: Benzene can form only one type of monosubstituted means that it cannot form different atoms just by replacing the position of the attached…

• A. Pyrrole
• B. Furan
• C. Thiophene
• D. All

Explanation: In benzene derivatives, all the atoms that make up the ring are carbon atoms.

• A. Increases electron density
• B. Decrease electron density on benzene
• C. Make benzene less reactive
• D. None of these

Explanation: The electron donating group such as the alkyl group donates electrons to the benzene ring and hence increases the density.

• A. Elimination
• B. Addition
• C. Substitution
• D. Dehydration

Explanation: There is no such evidence of an elimination reaction in Benzene since it completely destroys its stability.Benzene generally also resists…

• A. Ortho-xylene
• B. Para-xylene
• C. Para-methyl toluene
• D. Meta-methyl toluene

Explanation: Xylene is any of three organic compounds with the formula (CH3)2C6H4. They are derived from the substitution of two hydrogen atoms with…

• A. Alkyl group
• B. Benzyl group
• C. Phenyl group
• D. Ethyl group

Explanation: Reason: A benzene ring has the formula of C6H6. When a hydrogen atom is removed, this becomes C6H5. C6H5 is known as a phenyl group.

• A. Highly saturated
• B. Highly unsaturated
• C. Gives substitution reactions
• D. Gives elimination reactions

Explanation: Option B. Kekule formula with three double bonds demands a high degree of unsaturation from benzene while usually it exhibits a saturated…

• 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.

• 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…

• 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…

• 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.

• 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…

• 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…

• 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…

• 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…

• 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.

• 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…

• 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…

• 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.