InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
Which of the following cations are more stable than benzyl cation ?A. B. C. D. |
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Answer» Correct Answer - `(a,c,d)` |
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| 52. |
Cycloheptatrienyl cation is :A. Non-benzenoid and non-aromaticB. non-benzenoid and aromaticC. benzenoid and non-aromaticD. non-benzenoid and anti aromatic |
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Answer» Correct Answer - b |
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| 53. |
Which one of the following undergoes nitration reactions most readily?A. BenzeneB. AcetopheoneC. BenzaldehydeD. benzoic acid |
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Answer» Correct Answer - a |
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| 54. |
(A) Rate of nitration of benzene and hexadeuterobenzene are different. (R) C-H bond is stronger than C-D bond.A. If both (A) and ( R) are correct and ( R) is corrct explanation of (A).B. If both (A) and ( R) are correct but ( R) is not the corrct explanation of (A).C. If (A) is incorrect but ( R) is incorrect.D. If both (A) and ( R) are incorrect. |
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Answer» Correct Answer - e |
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| 55. |
The electrophile involved in the nitration of benzene isA. `NO^(+)`B. `NO_(2)^(+)`C. `NO`D. `NO_(3)^(-)` |
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Answer» Correct Answer - b |
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| 56. |
Nitration of benzene is carried out with :A. `HNO_(3)("dil.")`B. `HNO_(3)("conc.")`C. `HNO_(3)("fuming")`D. `(HNO_(3)("conc.")+H_(2)SO_(4)("conc.")` |
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Answer» Correct Answer - d |
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| 57. |
(A) Toluene undergoes nitration much more readily than benzene. ( R) It is due to electron relesing nature of `-CH_(3)` group which increases electron relectron density on benzene and electrophilic substitution reaction like nitrotion becomes faster.A. If both (A) and ( R) are correct and ( R) is corrct explanation of (A).B. If both (A) and ( R) are correct but ( R) is not the corrct explanation of (A).C. If (A) is incorrect but ( R) is incorrect.D. If (A) is incorrect but ( R) is incorrect. |
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Answer» Correct Answer - a |
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| 58. |
The order of decreasing reactivity towards an electrphilic reagent for the following, (i). Benzene (ii). Toluene. (iii). Chlorobenzoic acid. (iv). Phenol. Would.A. `IVgtIIIgtIIgtI`B. `IVgtIgtIIgtIII`C. `IIgtIgtIVgtIII`D. `IgtIIgtIVgtIII` |
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Answer» Correct Answer - a |
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| 59. |
Excess chlorine is passed through boiling toluene how many chloroderivatives would you get? |
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Answer» Correct Answer - 3 |
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| 60. |
Coal-tar is a main source of :A. aromatic compoundsB. alicyclic compundsC. aliphatic compoundsD. heterocyclic compounds |
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Answer» Correct Answer - a |
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| 61. |
Identify the correct order of reactivity in electrophilic substitution reaction of the following compounds. (1) Benzene (2) Toluene (3) Chlorobenzene, (4) Nitrobenzene.A. `4gt3gt4gt2`B. `4gt1gt3gt2`C. 4gt1gt2gt3`D. `4gt2gt1gt3` |
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Answer» Correct Answer - c |
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| 62. |
Mark the fraction of the coal-tar distillation in which benzene and toluene both are presetn:A. light-oilB. middle-oilC. heavy-oilD. anthracene-oil |
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Answer» Correct Answer - a |
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| 63. |
Which one of the following statements is wrong ?A. aromatic compounds are richer in carbon contentB. Aromatic conpounds burn with smoky flameC. Aromatic conpounds are generally unstableD. Aromatic conpounds show substitution reactions. |
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Answer» Correct Answer - c |
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| 64. |
Explain the following percentages of meta electrophilic substitutions. (a) `underset(4.4%)(C_(6)H_(5)CH_(3)),underset(15.5%)(C_(6)H_(5)CH_(2)CI),underset(33.8%)(C_(6)H_(5)CHCI_(2)),underset(64.6%)(C_(6)H_(5)C CI_(3))` (b) `underset(100%)(C_(6)H_(5)N(CH_(3))_(3)),underset(88%)(C_(6)H_(5)CH_(2)N(CH_(3))_(3)),underset(19%)(C_(6)H_(5)CH_(2)overset(+)N(CH_(3))_(3))` |
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Answer» (a) Successive replacement of hydrogen atoms in electron releasing group `(-CH_(3))` by electronegative chlorine atoms makes the group increasingly electron attracting and meta-directing. (b) The +ve charge on N makes the substituent electron attreacting and meta-directing. The positive charge decreases succuessively by inserting electron releasing `-CH_(2)` groups and thus o-, p-orientation dominates in `C_(6)H_(5)CH_(2)CH_(2)overset(+)N(CH_(3))_(3).` |
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| 65. |
Why does benzene undergo electrophilic substitution reactions easily and nucleophilic substitutions with difficulty? |
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Answer» Correct Answer - Benzene has high electron density due to the presence of three `pi-"electron pairs "(6pi-" electrons")` above and below the plane of the ring representing double bond. Due to the rich source of electrons `("delocalized "pi-"electrons")`, benzene attreacts the electrophle (slectron-deficient) reagents towards it and repels nuclephile (electron-rich) reagents. Therefore, benzene undergoes electrophilic substitution reactions easily and nuclephilic substituions with difficulty. |
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| 66. |
Which one of the following statements on the nitration of aromatic compounds is false?A. The rate of nitration of benzene is almost the same as that of hexadeuteriobenzene.B. The rate of nitration of toluene is greater than that of benzene.C. The rate of nitration of benzene is greater than that of hexadeuteriobenzene.D. Nitration is an electrophilic substitution reaction. |
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Answer» Correct Answer - C In electrophilic aromatci substitution such as nitration there is no isotope effect because the reaction is almost irreversible and the `C-H` bond of benzene ring is not broken in the rate-controlling step. |
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| 67. |
Some meta-directing substituents in aromatic substitution are given which one is the most deactivating?A. `SO_(3)H`B. `-COOH`C. `-NO_(2)`D. `-C-=H` |
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Answer» Correct Answer - C The correct order of deactivation is `-NO_(2) gt -C-=N gt -SO_(3)H gt - COOH` |
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| 68. |
Match the following : |
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Answer» Correct Answer - (1-h); (2-g); (3-j); (4-a); (5-c); (6-i); (7-b); (8-e); (9-d); (10-f). |
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| 69. |
When sodium formate is heated with soda lime, it forms:A. tolueneB. ethyleneC. benzeneD. aniline |
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Answer» Correct Answer - c |
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| 70. |
When sodium benzoate is heated with sodalime, the product formed isA. tolueneB. phenolC. benzeneD. benzaldehyde |
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Answer» Correct Answer - C `C_(6)H_(5)COONa+NaOHunderset(Delta)overset(CaO)tounderset("benzene")(C_(6)H_(6))+Na_(2)CO_(3)` The process is called decarboxylation. |
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| 71. |
Cyclooctatetraene isA. aromatic antiaromaticB. nonaromaticC. non-existentD. |
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Answer» Correct Answer - 3 Cycloctatetraene is conjugated carbocyclic polyene. On the basis of the number of `pie^(-)s(8pie^(-)s` equal to `4npie^(-)s)` , it is expected to be antiaromatic But it is non aromatic as it is not planar. Nonaromatics are nonplanar completely/incompletely conjugated carbocyclic polyenes having `(4n+2)pi` or `(4n)pie^(-)s` whose stability is comparable to their open chains analogs. |
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| 72. |
Aromatic compounds burn with a sooty flame becauseA. they have a relatively high percentage of hydrogenB. they have a relatively high percentage of corbonC. they have a ring structureD. they are reluctant to react with atmospheric oxygen. |
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Answer» Correct Answer - 2 Due to the high percentage of carbon, a lot of carbon remains unburnt and escapes as fine particles called soot. |
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| 73. |
If aromatic ring is substitued by more than groups then electrophilic aromatic substitution reaction take place according to more activating group. Type of group which donate electron in aromatic ring known as activating group Find out correct product of reaction .A. B. C. D. no reaction |
| Answer» Correct Answer - A | |
| 74. |
The major product formed on monobromination `((Br_(2))/(FeBr_(3)))` of the following compound. IsA. B. C. D. |
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Answer» Correct Answer - B When two different groups are present on a benzene ring the more powerful activating group generally determines the outcome of the reaction `-CH_(3)` is moderately activating while `-CH_(3)` is weakly activating. Thus, `-OCH_(3)` group determines the outcome of the reaction for `-OCH_(3)`, `-I_("effect")` follows the order :`ogtmgtp` while `+R_("effect")` follows the order: `ocongp`. Always remember that any kind of resonance effect never operates at meta position. Hence, substitution occurs mainly at the position para to the `-OCH_(3)` which is further activated by the ortho/para directing influence of `-CH_(3)` since steric effect are important in aromatic substitutions, substitution does not occur to an appreciable extent between meta substituents if another position is open. |
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| 75. |
In which reaction , polysubstitution takes place `:`A. B. C. D. |
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Answer» Correct Answer - B Alkyl groups are electron-releasing groups, an once one alkyl group is introduced into the benzene ring, it activates the ring toward further substitution. Thus, in friedel-crafts alkylation polyalkylation often occurs. |
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| 76. |
When is treated with nitrating mixture `(HNO_(3)+H_(2)SO_(4)),` we get :A. B. C. D. |
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Answer» Correct Answer - a |
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| 77. |
Indenify the end product (b) of the following sequence of reaction A. B. C. D. |
| Answer» Correct Answer - B | |
| 78. |
When phenol reacts with bromine in `CS_(2)` at a low temperature, the product is :A. m-bromophenolB. p-bromophenolC. o- and p- bromophenolD. 2,4,6- tribromophenol |
| Answer» Correct Answer - C | |
| 79. |
The product (Y) of the following sequence of reaction would is : A. B. C. D. |
| Answer» Correct Answer - C | |
| 80. |
Which of the following compounds will not rerranege on heating with `AlCl_(3)` ?A. B. C. D. |
| Answer» Correct Answer - D | |
| 81. |
Which product is formed at the end of following reaction ? A. B. C. D. |
| Answer» Correct Answer - A | |
| 82. |
Most stable carbocation is :A. B. C. D. |
| Answer» Correct Answer - D | |
| 83. |
Birch reduction of aniline will produce :A. B. C. D. |
| Answer» Correct Answer - D | |
| 84. |
Which one of the followingis the most reactive towards electrophilic attack?A. B. C. D. |
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Answer» Correct Answer - B `-NO_(2)` group is strongly deactivating, and `-Cl` and `-CH_(2)OH` groups are weakly deactivating but `OH` group is strongly activating thus compound (2) is the most reactive towards electrophilic aromatic substitution. |
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| 85. |
Which of the following is most reactive towards electrophilic substituion reaction ?A. B. C. D. |
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Answer» Correct Answer - a |
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| 86. |
Rate of substitution reaction in phenol is:A. slower than the rate of benzeneB. faster than the rate of benzeneC. equal to the rate of benzeneD. none of these |
| Answer» Correct Answer - B | |
| 87. |
Phenol and cyclohexanol can be distinguished by using :A. `FeCl_(3)`B. `Na`C. `PCl_(3)`D. `CH_(3)COCl` |
| Answer» Correct Answer - A | |
| 88. |
In chlorobenzen, the - Cl group :A. activates the benzene ring more, via resonamce effects than deactivaitng it via inductive effectB. deactivates the benzene ring more ,via inductive effect than activating it via resonamce effectsC. activates the benzene ring via resonance effects and deactives it via inductive effects. Both these effects are evenly matched.D. it is a et deactivating group with director characterisstic |
| Answer» Correct Answer - B | |
| 89. |
The compound which will be readily couple with benzene diazonium chloride is :A. benzoic acidB. phenolC. benzeneD. benzaldehyde |
| Answer» Correct Answer - B | |
| 90. |
Phenol can be converted into salicyclic acid by heating with :A. `CO_(2)` (under pressure ) and alkaliB. `C Cl_(4)` and alkaliC. `CHCL_(3)` and alkli, followed by oxidationD. all of the above |
| Answer» Correct Answer - D | |
| 91. |
Towards electrophilic substitution, the most reactive species will beA. AnilineB. NitrobenzeneC. Benzoic acidD. Acitanilide |
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Answer» Correct Answer - a |
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| 92. |
The compound with molecular formula `C_(8)H_(10)` which will give only two isomers on electrophilic substitution with `Cl_(2)//FeCl_(3)` or with `HNO_(3)//H_(2)SO_(4)` isA. p-dimethylbenzeneB. m-dimethylbenzeneC. dimethylbezeneD. ethylbenzene |
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Answer» Correct Answer - c |
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| 93. |
The electrophile, `E^((o+))` attacks the benzene ring to generate the intermediate `sigma`-complex. Of the following which `sigma`-complex is of lowest energy?A. B. C. D. |
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Answer» Correct Answer - 3 The `NO_(2)` group has a powerful electron-withdrawing influenece as it exerts both `-R` and `-I` effects `(-Rgt -I)`. This distabilizes the arenium cation 1,2, and 4 by intensifying their positive charge.On the other hand arenium ion (3) is most stable due to the absence of `NO_(2)` group. |
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| 94. |
Which of the following chemical systems is/are nonaromatic?A. IIB. IVC. II and IVD. None of these |
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Answer» Correct Answer - A all the species except II are planar and possess `(4n+2)pi` electrons which are completely delocalized. |
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| 95. |
The electrophilic aromatic substitution of a compound `C_(6)H_(5)Y` produces mainly a meta-disubstituted product. Among the following which one could be the substituent Y?A. `-NH_(3)`B. `-COOH`C. `-CH_(3)`D. `-Cl` |
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Answer» Correct Answer - B The `-NH_(2)` group is strongly activating the `-CH_(3)` group is weakly activating and the `-Cl` group is weakly deactivating all these are ortho-para directors one the other hand `-CO OH` group is moderately deactivating and has meta directing influence. |
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| 96. |
Which of the following is not a meta-directing group in electrophilic aromatic substitution?A. `-SO_(3)H`B. `-COOH`C. `-CN`D. `-NH_(2)` |
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Answer» Correct Answer - D The groups `-SO_(3)H,-COOH`, and `-CN` are all moderately deactivating and meta directing howerver, group `-NH_(2)` is strongly activating and ortho-para directing. |
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| 97. |
Which of the following structures corresponds to the product expected from the reaction of benzene (excess) with `CH_(2)Cl_(2)` in the presence of anhydrous `AlCl_(3)`?A. `C_(6)H_(6)overset(Cl)overset(|)(C)HC_(6)H_(5)`B. `C_(6)H_(5)CHCl_(2)`C. `C_(6)H_(5)C Cl_(2)C_(6)H_(5)`D. `C_(6)H_(5)CH_(2)C_(6)H_(5)` |
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Answer» Correct Answer - D It is friedel crafts alkylation `C_(6)H_(6)+Cl-CH_(2)Cl+C_(6)H_(6)underset(-2HCl)overset(AlCl_(3))toC_(6)H_(5)CH_(2)C_(6)H_(5)` |
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| 98. |
The concept of aromatic sectet was first proposed byA. RobinsonB. KekuleC. Dewar V.MeyerD. |
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Answer» Correct Answer - A Aromatic sextet theory was proposed by Robinson (1925). Its essential feature being that there are 6 electrons more that necessary to link together the six C atoms (of the benzene ring). These `6e^(-)` s, one being contributed by each C atom, form a closed group and it is this closed group which gives rise to aromatic properties. |
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| 99. |
Benzene reacts with `CH_(3)Cl` in the presence of anyhydrous `AlCl_(3)` to formA. chlorobenzeneB. benzyl chlorideC. xleneD. toluene |
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Answer» Correct Answer - C It is an example of friedel-crafts alkylation: `C_(6)H_(6)+CH_(3)Cloverset("Anhyd".AlCl_(3))tounderset("Toluene")(C_(6)H_(5)CH_(3))+HCl` |
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| 100. |
Which one of the following is not aromatic ?A. Cyclopentadienyl anionB. Cycloheptatrienyl cationC. CycloocatetraeneD. Thiophene |
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Answer» Correct Answer - c |
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