Free Benzene and Aromatic Compounds MCQs with Answers

• A. NO3
• B. NO+2
• C. NO2
• D. HNO3

Explanation: Nitration of benzene: Nitric acid and sulfuric acid used in nitration generate nitronium NO2+ ions as electrophiles.

• A. H2SO4
• B. HSO4
• C. SO+3
• D. SO3

Explanation: Sulfur trioxide or its protonated derivative is the actual electrophile in this electrophilic aromatic substitution.

• A. Low
• B. High
• C. Equal
• D. None

Explanation: hydrogen:carbon monoxide ratio of approximately 2:1 is required for hydrocarbon production. The by-product is water.

• A. One
• B. Two
• C. Three
• D. Four

Explanation: When 1 more substituent is introduced.(I) will give 3 isomeric products, ortho, meta and para disubstituted benzenes.(II) will produce…

• A. Vapour density method
• B. X-ray diffraction
• C. Elemental analysis
• D. Degradation method

Explanation: Benzene has a molecular weight, based on the formula of C6H6, of 78.1 amu's.

• A. 0.99 Å
• B. 1.09 Å
• C. 1.12 Å
• D. 1.397 Å

Explanation: Carbon-hydrogen bonds have a bond length of about 1.09 Å (1.09 × 10−10 m) and a bond energy of about 413 kJ/mol (see table below).

• A. sp
• B. sp2
• C. sp3
• D. None of these

Explanation: Each carbon in benzene is sp2 hybridised because each carbon atom is attached to 2 other carbon atoms and 1 Hydrogen atom and has no lone…

• A. 358.5 kJ/mole
• B. 119 kJ-mol-1
• C. 208 kJ-mol-1
• D. 150.5 kJ-mol-1

Explanation: Benzene has three double bonds, so we might expect its heat of hydrogenation to be -360 kJ/mol.

• A. Ni/200oC
• B. V2O5/450oC
• C. AlCl3/150oC
• D. Sunlight

Explanation: The oxidation of benzene by V2O5 in the presence of air produces maleic anhydride. The oxidation is carried out at 500 oC.

• A. Petroleum
• B. Coal-tar
• C. Living organism
• D. Dead marine animals

Explanation: Aromatic compounds are cyclic compounds in which all ring atoms participate in a network of π bonds, resulting in unusual stability.

• A. Benzene
• B. Thiophene
• C. Divinyl acetylene
• D. Xylene

Explanation: Acetylene on passing through red hot iron tube at 873K undergoes cyclic polymerization.

• A. CHO
• B. -SO3H
• C. -NO2
• D. Cl

Explanation: Chlorine withdraws electrons through inductive effect and releases electrons through resonance.

• A. 1.54oA
• B. 1.34oA
• C. 1.2oA
• D. 1.39oA

Explanation: C−C bond length in benzene is 1.39 ˚A.The bond length C-C ( single bond as in ethane ) is 1.54 Å and C=C ( double bond as in ethene is…

• A. C6H6 + CH4
• B. C6H5Cl
• C. C6H6 + CH3Cl
• D. C6H5Cl + CH4

Explanation: In the Friedel-Crafts synthesis of toluene, the reactants in addition to anhydrous AlCl3 are benzene (C6H6) and methyl chloride (CH3Cl).

• A. Biphenyl
• B. Dimethyl Ketone
• C. Diphenyl Ketone
• D. Methylphenyl Ketone

Explanation: Benzophenone is a widely used building block in organic chemistry, being the parent diarylketone. Benzophenone. Names.

• A. 2
• B. 3
• C. 4
• D. 5

Explanation: Xylene is an aromatic hydrocarbon with a single ring and two methyl groups attached to this ring in positions 1-2, 1-3 and 1-4, called…

• A. C10H8
• B. C10H10
• C. C10H12
• D. C12H12

Explanation: The chemical formula for naphthalene is C 10 H 8 . Naphthalene's chemical formula indicates that a single naphthalene molecule is composed…

• A. Chlorobenzene
• B. Benzoyl chloride
• C. Ortho-para dichlorobenzene
• D. Hexachlorobenzene

Explanation: When benzene is heated with chlorine in the presence of sunlight , it form benzene hexachloride.

• A. Resonance
• B. Inductive effect
• C. Both (a) and (b)
• D. Unpredictable

Explanation: The reaction of a substituted ring with an activating group is faster than benzene.

• A. Naphthalene
• B. Phenanthrene
• C. Anthracene
• D. Triphenylmethane

Explanation: Isolated Benzenoid Hydrocarbons: In isolated systems, two or more rings are joined to each other directly or through carbon chain.