Aromatic Hydrocarbons

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1Compound that has all C-C bonds of equal length( )Ethane

( )Acetylene

( )Benzene

( )Ethene

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2Which statement is not correct?( )A compound with 2 pi electrons can be aromatic

( )In an aromatic hydrocarbon there must be 4n+2 pi electrons

( )Each carbon in ring should be sp2 hybridized

( )An annulene with 10 pi electrons (10 is a Huckel number) is an aromatic hydrocarbon

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3Which one of the following compounds has lowest heat of combustion per mole?( )Ethene

( )Acetylene

( )Methane

( )Ethane

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4Which of the following statements is not correct?( )A compound with greater stability has lower heat of hydrogenation

( )Benzene being aromatic reacts readily with bromine water to form additional product

( )The actual electrophile in benzene sulphonation is SO3

( )A compound with greater stability has lower heat of combustion

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5Which of the following species is not a nucleophile?( )CN-

( )OH-

( )Benzene

( )None of these

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6Which of the following statements rules out the acccuracy of kekule structure of benzene?( )All C-C bonds in benzene are of equal length

( )Benzene has lower heat of hydrogenation

( )Benzene on bromination gives only one 1,2-dibromo benzene with no other isomer

( )All of the above

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7Which of the following compounds decolourize bromine water with the evolution of a colorless pungent gas?( )HC_=CH

( )H2C=CH2

( )Benzene

( )None of these

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8The resonance stabilization energy(in kcal/mol) of benzene is

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9On chlorination benzene forms a single monochlorobenzene without any isomer. It proves that( )Benzene sometimes behaves as non aromatic

( )Benzene is aromatic

( )All C-C bonds in benzene are identical

( )All C-H bonds in benzene are identical

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10Benzoyl chloride when treated with acid chloride yields( )Benzene

( )Benzaldehyde

( )Benzoic acid

( )Toluene

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11Benzene when treated with a mixture of CO and HCl in presence of anhydrous aluminium chloride gives( )Benzoyl chloride

( )Tolyl chloride

( )Benzaldehyde

( )Benzoic acid

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12Structure of benzene is( )Hexagonal planar

( )Trigonal planar

( )Tetrahedral

( )Hexagonal non planer

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13Toluene on oxidation in presence of alkaline KMnO4 produces( )Benzaldehyde

( )Benzyl alcohol

( )Benzoic acid

( )Phenol

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14In benzene C-C bonds are( )Double covalent

( )Single covalent

( )3 single and 3 double

( )Of the order 1.5

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15Pi electrons of benzene make it( )Electrophilic

( )Alicyclic

( )Hetrocyclic

( )Nucleophilic

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16The unexpected lower heat of hydrogenation of benzene is due to( )Delocalization of electrons and lower stability

( )Delocalization of electrons

( )Lower stability

( )Its high electrophilicity

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17Friedel craft acylation reaction is not successful in one of the following substrates, indicate that substrate.( )C6H5OH

( )C6H6

( )C6H5NO2

( )C6H5CH3

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18Which of the following is not aromatic hydrocarbon?( )Benzene

( )Naphthalene

( )Toluene

( )Cyclohexene

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19Introduction of a second methyl group in methyl benzene will give how many isomeric dimethylbenzenes?( )3

( )4

( )2

( )1

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20C-C bond length in benzene is (in angstroms)

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21When sodium benzoate is treated with soda lime (NaOH) benzene is formed. What is the other product?( )Ca(OH)2

( )Na2CO3

( )NaHCO3

( )CaCO3

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22Preparation of ethyl benzene by the reaction of bromobenzene, ethylbromide and sodium is called( )Wurtz reaction

( )Fittig reaction

( )Wurtz fittig reaction

( )None of these

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23Which of the following reaction is characteristic of benzene?( )Ozonolysis

( )Oxidation

( )Reduction

( )Electrophilic substitution reaction

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24Which of the following is not an electrophilic substitution reaction of benzene?( )Nitration

( )Free radical chlorination of benzene

( )Sulphonation

( )Friedel-Craft alkylation

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25Which of the following is an ortho-para directing group?( )CH3-

( )-C=_N

( )-COOH

( )NO2-

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26Which of the following is not an ortho-para directing group?( )-CHO

( )-OCH3

( )-NH2

( )-OH

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27Which of the following is a meta--directing group?( )-N+R3

( )-I

( )-N(CH3)2

( )-Br

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28The benzene molecule contains( )Two double bonds

( )Delocalized pi electron charge

( )One double bond

( )Three double bonds

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29Aromatic hydrocarbons are derivatives of

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30Which of the following acid can be used as catalyst in Friedel Craft's reaction?( )AlCl3

( )HNO3

( )NaCl

( )BeCl2

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31Benzene does not undergo( )Addition reactions

( )Substitution reactions

( )Oxidation reactions

( )Elimination reactions

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32Among the following, the compound that can be most readily sulphonated is( )Benzene

( )Toluene

( )Chlorobenzene

( )Nitrobenzene

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33Which compound is most reactive one( )Ethyne

( )Ethene

( )Ethane

( )Benzene

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34Aromatic compounds burn with sooty flame because( )They resist reaction with air

( )They have high percentage of hydrogen

( )They have a ring structure

( )They have high percentage of carbon

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35The conversion of n-hexane into benzene by heating in the presence of Pt is called( )Dezlkylation

( )Aromatization

( )Isomerization

( )Rearrangement

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36In the reaction: C6H6 + Cl2-------->C6H5Cl + HCl; benzene undergoes( )Nucleophilic addition

( )Nucleophilic substitution

( )Electrophilic substitution

( )Electrophilic addition

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37Which property of benzene may be directly attributed to the stability associated with its delocalised structure?( )Its enthalpy change of formation is positive

( )It does not conduct electricity

( )It has a low boiling point

( )It tends to undergo substitution rather than addition reaction

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38Organic compound formed when methyl benzene is heated with alkaline KMnO4 and the mixture is then acidified?

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39Which one of the following statement about C-C bond in benzene is true?( )It has greater bond energy than C=C bond

( )All bonds have same length

( )It is shorter than C=_C bond

( )It is weaker than C-C bond of alkanes

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40Which of the following group is meta directing?( )NO2

( )OH

( )CH3

( )Cl

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41Which of the following group is ortho and para directing?( )NO2

( )OH

( )CHO

( )COOH

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42Benzene is insoluble in( )Alcohol

( )Ether

( )Petrol

( )Water

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43Identify the compound formed when ethylene combines with water in the presence of 10% sulphuric acid and HgSO4 as catalyst.( )Methanol

( )Glycol

( )Ethanol

( )Carbinol

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44With AlCl3 as catalyst, benzene reacts with alkyl and acyl chlorides giving alkylated and acylated benzene respectively. This reaction is known as( )Nitration

( )Friedel craft reaction

( )Aldol condensation

( )Halogenation

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45Which one of the following belongs to meta directing group?( )Halogens

( )Keto group

( )Phenyl group

( )Alkyl group

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46The formula C6H5 represents( )Benzyl group

( )Vinyl group

( )Phenyl group

( )No such group exists

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47Benzene + Ozone----->Y. In this reaction Y is( )Benzene monoozonide

( )Benzene triozonide

( )Succinic acid

( )Benzene diozonide

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48Which reaction sequence would be best to prepare 3-chloro-aniline from benzene?( )Chlorination, nitration, reduction

( )Nitration, reduction, chlorination

( )Nitration, reduction, acylation, chlorination, hydrolysis

( )Nitration, chlorination, reduction

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49Benzene is obtained by fractional distillation of( )Anthracene oil

( )Middle oil

( )Light oil

( )Heavy oil

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50Which of the following species participate in sulphonation of benzene ring?( )HSO3-

( )SO3

( )SO2-

( )H2SO4

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51Which of the following possesses highest melting point?( )O-dichlorobenzene

( )Chlorobenzene

( )P-dichlorobenzene

( )M-dichlorobenzene

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52The treatment of benzene with isobutene in the presence of sulphuric acid gives( )N-butyl benzene

( )No reaction

( )Ter-butyl benzene

( )Isobutyl benzene

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53Octane number can be changed by( )Isomerisation

( )Alkylation

( )Cyclisation

( )All of these

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54Benzene can be obtained by heating either benzoic acid with X or phenol with Y. X and Y are respectively( )Soda lime and zinc dust

( )Soda lime and copper

( )Zinc dust and soda lime

( )Zinc dust and sodium hydroxide

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55Which of the following is prepared by a substitution reaction of benzene?( )Hexabromo cyclohexane

( )Cyclohexane

( )Acetophenone

( )Glyoxal

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56The term aromatic was derived from( )Russian

( )Latin

( )English

( )Greek word

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57Which of the following is not monocyclic aromatic compound?( )Benzoic acid

( )Benzene sulphonic acid

( )Benzaldehyde

( )Biphenyl

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58In which of the following rings are not fused together at ortho positions?( )Naphthalene

( )Diphenylmethane

( )Phenanthrene

( )Anthracene

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59Methyl benzene is also called

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60Substituted phenyl groups are called( )Aryl groups

( )Alkyl group

( )Acyl group

( )Phenyl groups

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61Benzene was discovered by Michael Faraday in

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62The empirical formula of benzene is determined by( )U.V

( )NMR spectra

( )IR spectra

( )Elemental analysis

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63C-C bond angles in benzene are

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64All C-H bond lengths of benzene ring is (in angstroms)

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65A six membered ring containing one double bond called( )Cyclohexene

( )Cyclohexane

( )Cyclohexadiene

( )None

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66Hybridization of each carbon atom in benzene is

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67Stability of aromatic compounds decrease with _____________ in the number of its resonance structure.( )Decreasee

( )Partially decreases

( )Increase

( )Remain constant

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68Benzene is not prepared from( )Bromo benzene

( )Phenol

( )Benzoic acid

( )Acetylene

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69Benzene is obtained from benzene sulphonic acid by treating with( )H2O

( )NaHCO3

( )NaOH

( )HCl

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70Which reaction is too vigorous to control?( )Bromination

( )Chlorination

( )Fluororination

( )Iodination

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71Sulphuric acid generates nitonium ion by reactin with( )Nitrogen gas

( )Potassium nitrate

( )Nitrous acid

( )Nitric acid

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72When benzene is burnt in free supply of air, it is completely oxidized to( )CO

( )CO2 + H2O

( )H2CO3

( )None

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73Benzene reacts with ozone to give( )Glycerin

( )Maleic anhydride

( )Benzoic acid

( )Glyoxal

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74Allkyl benzenes are readily oxidized by acidified( )MnO4

( )K2CO3

( )KMnO4

( )H2SO4

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75How many isomeric distributed products are obtained by the introduction of second group in the ring?( )2

( )3

( )4

( )None

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76The electron releasing effect of methyl group is significant and it makes ring a good( )Nucleophilic

( )Nucleophobic

( )Electrophilic

( )Hydrophobic

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77Which of the following increase the chemical reactivity of benzene ring?( )Halogens

( )Meta directing group

( )Ortho/para directing groups except halogens

( )All ortho/para directing groups

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78Which class of compounds is more reactive?( )Alkane

( )Alkene

( )Alkyne

( )None

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79Benzene does not undergo polymerization and it is also resistant to( )Oxidation

( )Ozonolysis

( )Alkylation

( )Reduction

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80Which of the following is m-xelene?( )1,2-dimethyl benzene

( )1,3-dimethyl benzene

( )1,4-dimethyl benzene

( )1,5-dimethyl benzene

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81The nitration of benzene takes place when it is heated with a mixture of conc.HNO3 and conc.H2SO4 at 50 C in ratio of( )1:1

( )1:2

( )2:1

( )1:3

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82The three alternate single and double bonds in the benzene ring are called( )Conjugate bonds

( )Conjugate/resonating bonds

( )None of these

( )Resonating bonds

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83The difference between amount of heat actually released and that of calculated is called( )Bonding energy

( )Resonance energy

( )Transition energy

( )Activation energy

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84All are ortho & para directing except( )NR3

( )X

( )NH2

( )OH

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85Substitution of halogens in benzene ring require catalyst ________________.

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86Which one does not decolourize KMnO4?( )Alkynes

( )Alkenes

( )Benzene

( )All these

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87When alkyl is treated with chlorine in the presence oof sunlight( )1,4-dichloro product is formed

( )1,3,5-trichloro product is formed

( )Only alkyl group is substituted

( )1,3-dichloro product is formed

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88Benzene is prepared from n-hexane in the presence of catalyst( )Cr2O3

( )Al2O3

( )SiO2

( )All these

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89During nitration of benzene, the active nitrating agent is( )NO^-

( )HNO3

( )NO^+

( )NO2^+

Single Answer