two are the same length and the third one is different
Q.3.
Which of these are not evidence for the delocalised model?
X-ray crystallography shows all bonds are same length
Benzene is resistant to bromination
Enthalpy of hydrogenation shows it is less than expected
Enthalpy of hydrogenation shows it is more than expected
Q.4.
The bond length of c-c bond in benzene is
1.45 A
1.38A
1.33A
1.23A
Q.5.
The color of Kmno4 changes in test for unsaturation reaction is due to
oxidation
reduction
hydrogenation
all
Q.6.
Which of them is Hetero cyclic aromatic compound
benzene
Toluene
Pyridine
Xylene
Q.7.
What is 'n' in Huckel rule
number of ring
number of catom
any integer
none
Q.8.
What happens when benzene reacts with bromine in ferric bromide?
it forms dibromo benzene
forms mono bromo benzene
both
none
Q.9.
How many electrons are there in the delocalised pi electron system in benzene?
3
6
9
12
Q.10.
A reagent that could be used to distinguish between benzene and cyclohexene is ...
Acidified K2Cr2O7
Tollens reagent
Bromine water
Sodium carbonate
Q.11.
The formula for the nitronium ion is
NO2+
NO2
NO2+
NO22+
Q.12.
What form of reaction mechanism is benzene normally involved in?
Electrophillic substitution
Electrophillic addition
Electophillic addition elimination
Nucleophilic substitution
Q.13.
The nitration of benzene uses a nitrating mixture of concentrated nitric acid and concentrated sulfuric acid. HNO3 + 2H2SO4 → NO+ H3O+ + 2HSO4–Which statement is correct?
HNO3 acts as a base.
HNO3 acts as a catalyst.
HNO3 acts as an electrophile.
HNO3 acts as a reducing agent.
Q.14.
An electrophile is ...
an electron pair donor
an electron pair acceptor
a negatively charged ion
a proton donor
Q.15.
C-C bonds formed in benzene by
Sp-S overlapping
Sp2- sp Overlapping
Sp2-Sp2 overlapping
S-sp2 overlapping
Q.16.
Write the name of scientist who gave the structure of benzene first.
Kekule
August Kekulé
None of these
Q.17.
Resonance stabilized is due to
strong covalent bond
strong pi bond
delocaloisation of pi electrons
delocalisation of sigma electrons
Q.18.
What is produced when benzene reacts with chlorine in the presence of an iron catalyst?
only chlorobenzene
chlorobenzene and chlorine atoms
chlorobenzene and hydrogen chloride
chlorobenzene and water
Q.19.
Alcohol can be produced by the following methods except
fermentation of glucose
catalytic addition of steam to ethene
cracking of long chain hydrocarbon
Q.20.
Which of the following is considered a disubstituted benzene?
Phthalic acid
Benzoic acid
Acetophenone
Benzophenone
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