12th class (fsc) Chemistry unit 9 MCQs
51. The electrophil ik aromitc sulphonation is:
a. SO3
b. H2 SO4
c. SO3+
d. HSO4
52. Aromatic compounds burns with sooty flame because:
a. They have higher percentage of carbon
b. They have high percentage of hydrogen
c. They resist reaction with air
d. They have a ring structure
53. The conversion of n-hexane into benzene by heating in the presure of Pt is called:
a. Dealkulation
b. Isomerization
c. Rearrangement
d. Aromatization
54. In which of the following compounds, the benzene rings are isolated:
a. Anthracene
b. Diphenyl methane
c. Phenenthrene
d. Naphthalene
55. Which one of the following is not hetrocyclic compound?
a. Furan
b. Thiophene
c. Pyrrole
d. Anthracene
56. Ortho and para derivatives are obtained by halogenation of:
a. Benzaldehyde
b. Nitrobenzene
c. Benzene
d. Toluene
57. Aromatic hydrocarbons are derivatives of:
a. Benzene
b. Paraffins
c. Cyclohexane
d. Alkene
58. How many pi electrons in benzene:
a. 12
b. 6
c. 14
d. 3
59. How many resonance structures of benzene are known:
a. 5
b. 3
c. 6
d. 4
60. Resonance energy of benzene is:
a. 155
b. 150.5
c. 145
d. 140.5
61. The type of reaction which benzene may undergo:
a. Oxidation
b. Addition
c. Substitution
d. All of these
62. Aronatization if n- hexane gives:
a. Benzene
b. Cycloheptane
c. Toluene
d. Cyclohexane
63. The electrophile in aromatic sulphonation is:
a. SO3
b. H2SO4
c. None of these
d. H2SO3
64. Acetylene polymerizes to make:
a. Butane
b. 1,3,5- cycloexatriene
c. Hexane
d. Benzene
65. Which of th following is used as catalyst, when benzene reacts with acetyl chloride to give acetophenone?
a. Ni
b. FeCI3
c. AI2O3
d. AICI3
66. M-chloronitro benzne is prepared by:
a. Nitration of benzene
b. Nitration of chlorobenzene
c. Nitration of mchloro benzene
d. Chlorination of nitro benzene
67. Benzene is prepared from cyclehexane by the process called:
a. Dehydrogenation
b. Hydrogenation
c. None of these
d. Aromatization
68. Among the following the compound that can be sulphonated most easily is:
a. Nitro benzene
b. Toluene
c. Chloro benzene
d. Benzene
69. The benzene ring is oxidized to maleic anhydride when strngly heated with:
a. AICI3 /150oC
b. Ni/200oC
c. Sunlight
d. V2O5 /45oC
70. Meta directing groups:
a. Neither release nor withdraw electrons of the benzene ring
b. Withdraw electrons from the benzene
c. Release of electrons to the benzene ring
d. None of these
71. Nitration of toluene take place at:
a. O-position
b. M-position
c. O-Position and P-position
d. P-position
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