Benzene(General Knowledge > General Science ) Questions and Answers

Question 1. Which of the statement is TRUE about electrophilic aromatic substitution?
  1.    Substitution of hydrogen atom in methane by chlorine atom
  2.    Substitution of hydrogen atom in benzene by NO2+
  3.    Substitution of chlorine atom in ethanoyl chloride by CH3O-
  4.    Substitution of -OH in ethanol by CI-
Explanation:-
Answer: Option B. -> Substitution of hydrogen atom in benzene by NO2+
Question 2. Which of the following reagent does not react with benzene?
  1.    Concentrated H2SO4
  2.    HNO3/ H2SO4
  3.    Iodoehane in the presence of iron
  4.    Sodium hydroxide solution
Explanation:-
Answer: Option D. -> Sodium hydroxide solution
Question 3. Nitronium ion, NO2+, attacks the electrons of the aromatic ring of benzene
  1.    Free radical substitution
  2.    Electrophilic aromatic substitution
  3.    Nucleophilic aromatic substitution
  4.    Electrophilic aromatic addition
Explanation:-
Answer: Option B. -> Electrophilic aromatic substitution
Question 4. Which of the following will produce chlorobenzene when chlorine was passed through it?
  1.    Iodobenzene at 20⁰C
  2.    Bromobenzene in the presence of iron
  3.    Benzene in the presence of iron
  4.    Benzene in the presence of light
Explanation:-
Answer: Option C. -> Benzene in the presence of iron
Question 5. Which of the reagents below does NOT react with methylbenzene?
  1.    Bromine gas/iron catalyst
  2.    Aqueous bromine in catalyst
  3.    Acidified potassium manganite (VII)
  4.    Dilute sulphuric acid
Explanation:-
Answer: Option D. -> Dilute sulphuric acid
Question 6. The species that attacks the benzene molecule in the nitration of benzene using a mixture of concentrated sulphuric acid and concentrated nitric acid is
  1.    NO2
  2.    NO2+
  3.    HNO3
  4.    NO3 -
Explanation:-
Answer: Option B. -> NO2+
Question 7. Which of the following is FALSE about the property of benzene molecule?
  1.    It is a planar molecule.
  2.    It is stabilised by delocalisation of ℼ electrons.
  3.    Each carbon atom undergoes sp hybridisation.
  4.    Its typical reaction is electrophilic substitution.
Explanation:-
Answer: Option C. -> Each carbon atom undergoes sp hybridisation.
Question 8. How many degrees of unsaturation is present in benzene?
  1.    5
  2.    4
  3.    6
  4.    3
Explanation:-
Answer: Option B. -> 4
Question 9. How many delocalised electrons (pi electrons) are there for each benzene molecule?
  1.    2
  2.    3
  3.    6
  4.    12
Explanation:-
Answer: Option C. -> 6
Question 10. What is the molecular formula of Benzene?
  1.    C6H12
  2.    C6H6
  3.    C6H10
  4.    C8H8
Explanation:-
Answer: Option B. -> C6H6
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