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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 halogens is employed for the test of unsaturation?A. IodineB. BromineC. ChlorineD. Fluorine |
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Answer» Correct Answer - B The formation of addition compounds with `Br_(2)` serves as a test for the presence of carbon-carbon multiple bonds. If we add bromine to an alkene (or alkyne), the red brown color of the bromine solution disappears almost instantly as long as the alkene (or alkyene) is present in excess. This behaviour contracts markedly with that of alkanes which do not react appreciably with `Br_(2)` or `Cl_(2)` at room temperature and in the absence of light. Although `I_(2)` solution is also colored, it is not used because reaction with `I_(2)` is quite slow. |
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| 52. |
What are X and Y in the reaction `C_(2)H_4+H_(2)SO_(4)overset(80^(@)C)toXunderset(Delta)overset(H_(2)O)toY`A. `C_(2)H_(6),C_(2)H_(5)OH`B. `C_(2)H_(4),C_(2)H_(5)SH`C. `C_(2)H_(5)OSO_(3)H,C_(2)H_(5)OH`D. `C_(2)H_(4),C_(2)H_(5)OH` |
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Answer» Correct Answer - C |
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| 53. |
2-mthylpent-2-ene on ozonolysis will giveA. Only propanalB. Propanal and ethanalC. Propanone-2 and ethanalD. propanone-2 and propanal |
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Answer» Correct Answer - D |
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| 54. |
Match the following |
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Answer» Correct Answer - A::B::C::D |
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| 55. |
Arrange the following alkyl halides in decreasing order of the rate or `beta`-elimination reaction alcoholic KOH. A. `CH_(3)-underset(CH_(3))underset(|)overset(H)overset(|)(C)-CH_(2)Br` B. `CH_(3)-CH_(2)-Br` C. `CH_(3)-CH_(2)-CH_(2)-Br`A. igtiigtiiiB. iiigtiigtiC. iigtiiigtiD. igtiiigtii |
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Answer» Correct Answer - D |
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| 56. |
What is the experimentally-determined rate expression for the base-induced `beta`-elimination?A. `"Rate"=[RX][B^(-)]^(2)`B. `"Rate"=[RX]^(2)[B^(-)]`C. `"Rate"=K[RX][B^(-)]`D. `"Rate"=K[RX]` |
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Answer» Correct Answer - C The synthesis of an alkene by dehydrohalogenation is almost always better achieved by an `E2` reaction, which follows second-order kinetics. |
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| 57. |
Which of the following alcohols is most easily dethydrated ?A. Butan-`1`-olB. `2`-Methylpropane-`2`-olC. Butan -`2`-olD. `2`-Methylpropan-`1`-ol |
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Answer» Correct Answer - B It is a tertiary alcohol. The order of relative ease with which alcohols undergo dehydration is as follows: `underset(3^(@)"alcohol")(R_(3)COH)gtunderset(2^(@)"alcohol")(R_(2)CHOH)gtunderset(1^(@)"alcohol")(RCH_(2)OH)` |
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| 58. |
Which of the following reaction will yield 2,2-dibromopropane?A. `CH_(3)-CH=CH_(2)+HB rto`B. `CH_(3)-C-=CH+HB rto`C. `CH_(3)-CH=CHB rto+HB rto`D. `CH-=CH+HB rto` |
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Answer» Correct Answer - B |
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| 59. |
Ethyl alcohol is heated with concentrated `H_(2)SO_(4) at 170^(@)C`. The product formed isA. ethyl hydrogen sulphateB. diethyl sulphateC. ethyleneD. diethyl ether |
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Answer» Correct Answer - C `underset(OH)underset(|)CH_(2)-underset(OH)underset(|)CH_(2)underset(170^(@)C)overset(Conc.H_(2)SO_(4))rarrCH_(2)=CH_(2)+H_(2)O` Ethyl hydrogen sulphate, `C_(2)H_(5)OSO_(2).OH`, is formed in the cold, but on heating to about `170^(@)C`, it decomposes into ethylene and sulphuric acid. |
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| 60. |
`(CH_(3))_(3)C CH_(2)-CBr(CH_(3))_(2)overset(Heat)rarr` The major product isA. `(CH_(3))_(3)C CH_(2)C(CH_(3))=CH_(2)`B. `(CH_(3))_(3)C CH=C(CH_(3))_(2)`C. `CH_(2)=underset(CH_(3))underset(|)C-overset(CH_(3))overset(|)CHCH(CH_(3))_(2)`D. `(CH_(3))_(2)C=underset(CH_(3))underset(|)C CH(CH_(3))_(2)` |
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Answer» Correct Answer - A On account of the presence of a bulky group at the `beta-C`, elimination proceeds in accordance with the Hofmann rule. |
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| 61. |
Great care must be taken in handling diborane and alkylboranes because they ignite spontaneously in air with a flame.A. blueB. yellowC. greenD. red |
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Answer» Correct Answer - C The solution of `THF:BF_(3)` is considerrably less prone to spontaneous ignition but still must be used in an inert atomosphere and with care. |
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| 62. |
Propene on reaction with diimide, `HN = NH`, givesA. `(CH_(3)CH_(2)CH_(2))_(2)NH, NH_(3)`B. `CH_(3)underset(NH_(2))underset(|)(CH)-underset(NH_(2))underset(|)(CH_(2))`C. `C_(3)CH_(2)CH_(3), N_(2)`D. `CH_(3)-underset(NH_(2))underset(|)(CH)CH_(3)-NH_(3)` |
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Answer» Correct Answer - C `HN=NH`( dimide) donates its hydrogens to `gt C=Clt` `CH_(3)CH=CH_(2)overset(NH=NH)rarrCH_(3)CH_(2)CH_(3)++N_(2)` |
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| 63. |
2-Methyl propene on treatment with acidic potassium permanganate givesA. Propanal, `CO_(2)`B. Propanone, `CO_(2)`C. Propanoic acid, `CO_(2)`D. Butanone, `CO_(2)` |
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Answer» Correct Answer - B |
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| 64. |
Consider the following reaction `X+HCl overset(Anh." "AlCl_(3))toC_(2)H_(5)Cloverset(Aq." "KOH)toY`. Y can be converted to X on heating with.A. `Al_(2)O_(3),350^(@)C`B. `Cu,300^(@)C`C. `Ca(OH)_(2)+CaOCl_(2),60^(@)C`D. `NaOH//I_(2),60^(@)C` |
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Answer» Correct Answer - A |
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| 65. |
`C_(2)H_(5)Cloverset("Alcoholic "KOH)toAoverset(dil.H_(2)SO_(4)//H_(2)O)toB` Here A and B areA. `C_(2)H_(5)OH,C_(2)H_(4)`B. `C_(2)H_(4),C_(2)H_(5)OH`C. `Ca(OH)_(2)+CaOCl_(2),60^(@)C`D. `NaOH//I_(2),60^(@)C` |
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Answer» Correct Answer - B |
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| 66. |
0.37g of an alcohol (A) when treated with `CH_(3)MgI` liberates 112 ml of `CH_(4)` at STP. Alcohol (A) on dehydration gives alkene (B) which on ozonolysis gives acetone as one of the product along with (C). (A) when treated with benzene in acidic medium given (D) which does not give benzoc acid on oxidation. (A) on oxidation gives acid (E) having same number of C-atoms. Q. From given data molecular formula of (A) isA. `C_(5)H_(11)OH`B. `C_(4)H_(9)OH`C. `C_(6)H_(13)OH`D. `C_(4)H_(7)OH` |
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Answer» Correct Answer - B |
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| 67. |
The dehydration of alcohols to form alkenes is catalyzed byA. an acidB. a baseC. either an acid or a baseD. neither an acid nor a base |
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Answer» Correct Answer - A `CH_(3)CH_(2)OHunderset(H_(2)SO_(4),170^(@)C)overset("Excess concentrated")rarrCH_(2)=CH_(2)` |
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| 68. |
S-I: 2-methyl butan-2-ol o heating with `H_(2)SO_(4)` gives 2-methyl but-2-ene. S-II: The dehydration of `3^(@)` alcohols occurs through carbocation formation allowed by elimination of `H^(+)`A. S-I & II are correct, S-II is correct explanation of S-IB. S-I&II are correct, S-II is not correct explanation of S-IC. S-I is true, but S-II is false.D. S-I is false, ut S-II is true |
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Answer» Correct Answer - A |
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| 69. |
Dehydration of ……. Alcohols is carried out with concentrated sulphuric acid.A. PrimaryB. secondaryC. tertiaryD. all of these |
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Answer» Correct Answer - A The acid acts as dehydrating agent. The dehydration of `2^(@) and 3^(@)` alcohols is best carried out using dilute `H_(2)SO_(4)` because the alkenes formed from this alcohol tend to polymerize under the influence of concentrated acid. |
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| 70. |
Assertion (A): Dehydration of alcohols can be carried out with Conc `H_(2)SO_(4)` but not with conc HCl Reason (R): `H_(2)SO_(4)` is dibasic while HCl is monobasic. (1). Both A and R are true and R is the correct explanation to A (2). Both A and R are true and R is not the correct explanation to A (3). A is true but R is false (4). A is false but R is true |
| Answer» Correct Answer - 2 | |
| 71. |
In the preparation of alkene from alcohol using `Al_(2)O_(3)`, which is effective factor?A. Porosity of `Al_(2)O_(3)`B. TemperatureC. ConcentrationD. Surface area of `Al_(2)O_(3)` |
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Answer» Correct Answer - D Alkenes can be made by passing the alcohol vapor over a catalust of alumina `(Al_(2)O_(3))`. Alumina is a good chemical adsorbent. The extent of adsorption of alcohol vapour depends upon the surface area of `Al_(2)O_(3)`. |
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| 72. |
The number of the following reagents can be used for the above conversion is (i). Conc. `H_(2)SO_(4)//Delta` (ii). `Al_(2)O_(3)//Delta` (iii). `ThO_(2)//Delta` |
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Answer» Correct Answer - 1 |
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| 73. |
One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44u. The alkene is:A. EtheneB. PropeneC. 1-buteneD. 2-butene |
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Answer» Correct Answer - D |
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| 74. |
Statement `I:` `1-`Butene on reaction with `HBr` in the presence of a peroxide produces `1-` bromobutane. Statement `II:` It involves the formation of a primary radical.A. S-I & II are correct, S-II is correct explanation of S-IB. S-I&II are correct, S-II is not correct explanation of S-IC. S-I is true, but S-II is false.D. S-I is false, ut S-II is true |
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Answer» Correct Answer - C |
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| 75. |
An unknown alkene of molecular formula `C_(8)H_(16)` on oxidation with hot alkakline `KMnO_(4)` yields propanoic acid and pentanoic acid. Find the structure of the alkene. Strategy: `C_(8)H_(16)underset((2)H_(3)O^(+))overset((1)KMnO_(4)`,H_(2)O,OH^(-)"heat")rarrCH_(3)CH_(2)-underset("acid")underset("Pentanoic")overset(O)overset(||)C-OH+HO-underset("acid")underset("Pentanoic")overset(O)overset(||)C-CH_(2)CH_(2)CH_(2)CH_(3)` Remove the `OH` groups and join the carboxylic acid carbons by a double bond to get the alkene. |
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Answer» The known alkene is either cis-or-trans-oct-`3-"ene"`. Oxidative cleavage takes place as follows: `underset("Unknown alkane either cis-or trans -oct -3 -ene")(CH_(3)CH_(2)-CH!=CH-CH_(2)CH_(2)CH_(2)CH_(3))`underset((2)H_(3)O^(+))overset((1)KMnO_(4),H_(2)O`,`OH^(-)" heat")to` `CH_(3)CH_(2)-overset(O)overset(||)C-OH+CH_(3)CH_(2)CH_(2)CH_(2)-overset(O)overset(||)C-OH` |
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| 76. |
An alkene on vigorous oxidation with `KMnO_(4)` solution produces only acetic acid. The alkene is .A. `CH_(3)-CH_(2)-CH=CH_(2)`B. `CH_(3)-CH=CH-CH_(3)`C. `(CH_(3))_(2)-C=CH_(2)`D. `CH_(3)CH=CH_(2)` |
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Answer» Correct Answer - B |
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| 77. |
Propene is allowed to react with diobrane and the product is treated with alkaline `H_(2)O_(2)`. The final product isA. propanalB. propanoneC. propan`-1-ol`D. propen`-2-ol` |
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Answer» Correct Answer - C `3CH_(3)CH=CH_(2)underset(Ether)overset(B_(2)H_(6))rarr(CH_(3)CH_(2)CH_(2)-)_(3)Bunderset(Ether)overset(H_(2)O_(2)//OH^(-))rarr3CH_(3)CH_(2)CH_(2)OH` It is an example of hydrocarbon-oxidation. The net regiospecificity of the addition is anti-Markovnikov. |
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| 78. |
The electrophile in hydrocarbon isA. `BH_(3)`B. `(BH_(3))_(2)`C. `(BH_(3))_(3)`D. `H^(+)` |
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Answer» Correct Answer - A `BH_(3)` is the electrophile. It leads to the `C` with greater number of hydrogens. Thus, it is a Markvniko-type addition. `BH_(3)` by itself does not exist. Its dimer `B_(2)H_(6)` is dissolved in a coodinate convalent bond with the `O` of the ether. |
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| 79. |
Work out all possible structural isomeric alkenes corresponding to `C_(5)H_(10)` and also give their `IUPAC` names. Strategy: Alkene isomers are deduced by writing the different `C` skeletons and then introducing the double bond at different locations. The possible skeletons are `C-C-underset((I))C-C-C,C-underset((II))underset(C)underset(|)C-C-C,C-underset((III))underset(C )underset(|)overset(C )overset(|)C-C` |
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Answer» First explore all the possibilities of placing the double bond for the straight-chain skeleton (I): (i) `CH_(3)CH_(2)underset("Pent-1-ene")(CH_(2))CH=CH_(2)` (ii) `CH_(3)CH_(2)underset("Pent-2-ene")(CH=)CHCH_(3)` Next explore all the possibilities of positioning the double bond for the branched-chain skeleton(II): (iii) `overset(4)(CH_(3))-^(3)underset(3-"Methylbut-1-ene")(overset(CH_(3))overset(|)(CH)-overset(2)C=overset(1)(C)H_(2))` (iv) `overset(1)CH_(3)-underset(2-"Methylbut-2-ene")(underset(CH_(3))underset(|)overset(2)(CH)=overset(3)CH-overset(4)CH_(3)` (v)`overset(1)CH_(2)=underset(2-"Methybut-1-ene")(underset(CH_(3))underset(|)overset(2)(CH)-overset(3)CH-overset(4)CH_(3)` The " central " `C`" atom " of (III)" is a quarternary "`C` "atom and cannot form a double bond to give an alkane". |
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| 80. |
Assertion : Cyclopentadienyl anion is much more stable than allyl anion. Reason : Cyclopentadienyl anion is aromatic in character.A. S-I & II are correct, S-II is correct explanation of S-IB. S-I&II are correct, S-II is not correct explanation of S-IC. S-I is true, but S-II is false.D. S-I is false, ut S-II is true |
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Answer» Correct Answer - A |
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| 81. |
Hydroboration-Oxidation of `CH_(3)CH=CH_(2) ` produces (1). `CH_(3)CH_(2)CH_(2)OH` (2). `CH_(3)CH(OH)CH_(2)` (3). `CH_(3)CH(OH)CH_(2)OH` (4). `CH_(3)COCH_(3)` |
| Answer» Correct Answer - 1 | |
| 82. |
The stereospecificity of the reactions is a very good evidence that E2 reactions proceed through an anti-periplanar transition state. More evidence comes from the reactions of substituted cyclohexanes. Generally, all cyclohexanes are most stable in chair conformations. we know that substituets on cyclohexanes can be parallel with one another only if they are both axial. an equatorial C-X bond is anti-periplanar only to C-C bonds and cannot take part in an elimination. for unsubstitueted cyclohexyl halides treated with base, this is not a problem because, although the axial conformer is less stable, there is still a significant amount present and elimination can take place from thi conformer Q. Let us consider the stable cis-and trans-isomers of 4-tert-butylcyclohexyl-p-toluene sulphonate.A. Cis-isomer undergoes `E_(2)` reactionB. Trans-isomer undergoes `E_(2)` reactionC. Trans-isomer does not undergo `E_(2)` reactionD. Both A and C are correct. |
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Answer» Correct Answer - D |
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| 83. |
S-I: The boiling point of cis-1,2-dichloroethene is higher than corresponding trans-isomer. S-II: The dipole moment of cis-1,2-dichloroethene is higher than trans isomer.A. S-I & II are correct, S-II is correct explanation of S-IB. S-I&II are correct, S-II is not correct explanation of S-IC. S-I is true, but S-II is false.D. S-I is false, ut S-II is true |
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Answer» Correct Answer - A |
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| 84. |
The reaction `BrCH_(2)CH_(2)Br+Znoverset(CH_(3)CO_(2)H)rarrCH_(2)=CH_(2)+ZnBr_(2)` proceeds by the …… mechanism.A. `E1-cB`B. `E2`,syn-eliminationC. `E2`,anti eliminationD. `E1` |
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Answer» Correct Answer - C Both addition ( to the alkene) and elimination ( from the dibromide) of the `Br` atoms are predominantly trans, i.e., steroselective. These observations may be explained in terms of the formation of a bridged intermediate. It also folowes from this that the configuration of the protected alkene remains unchanged. |
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| 85. |
Product may not beA. B. C. D. |
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Answer» Correct Answer - A::B::D |
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| 86. |
In the reaction The product X is.A. B. C. D. |
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Answer» Correct Answer - D |
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| 87. |
In the following reaction Product A isA. B. C. D. |
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Answer» Correct Answer - A |
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| 88. |
`1`-Bromobutane is treated with sodium ethoxide in ethanol. The major product obrained isA. trans-but-`2`-eneB. cis-But-`2`-eneC. but-`1`-eneD. `1`-ethoxybutane |
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Answer» Correct Answer - C `CH_(3)CH_(2)CH_(2)CH_(2)Brunderset("mechanism")overset(E2)rarrCH_(3)CH_(2)CH=CH_(2)` No carbocation is formed, hence no rearrangement. |
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| 89. |
While of the following compounds will exhibit geometrical (or cis-trans) isomerism? (i) `CH_(3)CH=CHCH_(2)CH_(3)` (ii) `C_(6)H_(5)CH=CHCH_(3)` (iii) `CH_(2)=C(CH_(3))_(2)` `(CH_(3))_(2)C=CH-C_(2)H_(5)` Strategy: Essential requirement for any alkene to exhibit geometrical isomerism is that each of the double bonded carbon atoms should be attached to two different atoms or groups of atoms: `m!=n and p!=r`. Notice that `m` and `p` may be same or different Similarly, `n and r` may be same or different. |
| Answer» Structures (i) and (ii) will exhibit geometrical isomerism. Structures (iii) and (iv) fail to do so because two identical atosm and//or groups are attached to one of the doubly bonded carbon atoms. | |
| 90. |
The number of structural isomers (open chain) possible for `C_(5)H_(10)` areA. 6B. 4C. 5D. 3 |
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Answer» Correct Answer - C |
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| 91. |
the addition of HBr to an alkene in the presence of a peroxide isA. a nucleophilic addition via an alkyl anoin intermediateB. an electrophilic addition via an alkyl cation intermediateC. a free-radical addition via a `beta`-bromo alkyl radical intermediateD. a free-radical addition via an `alpha`-bromo alkyl radical intermediate |
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Answer» Correct Answer - C `Br^(*)+H_(2)C=CH-R rarr Brunderset(alpha)(C)H_(2)-underset(beta)overset(*)(C)H-R` `overset(H-Br)to BrCH_(2)CH_(2)R + Br^(*)rarr` |
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| 92. |
Rank the following in the increasing order of rate of reaction with HBr. A. RgtPgtQB. RgtQgtPC. PgtRgtQD. PgtQgtR |
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Answer» Correct Answer - A |
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| 93. |
Two moles of formaldehyde can be obtained by the followingA. Ozonolysis of acetylene and followed by hydrolysisB. Ozonolysis of ethylene and followed by hydrolysisC. Ozonolysis of propene and hydrolysisD. Ozonolysis of 2-butene and hydrolysis. |
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Answer» Correct Answer - B |
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| 94. |
In which of the following will Kharasch effect operate?A. `CH_(3)-CH_(2)-CH=CH_(2)+HCl`B. `CH_(3)-CH_(2)-CH=CH_(2)+HBr`C. `CH_(3)-CH=CH-CH_(3)+HBr`D. `CH_(3)-CH_(2)-CH=CH_(2)+HI` |
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Answer» Correct Answer - B |
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| 95. |
`2CH_(3)-underset(Ph)underset(|)(C)=CH_(2)overset(HF)tounderset(("major"))((A))`. Product (A) isA. B. C. D. |
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Answer» Correct Answer - C |
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| 96. |
`H_(2)C=CH-CH_(2)-CH_(3)overset(X)tounderset(Br)underset(|)(C)H_(2)-CH_(2)-CH_(2)-CH_(3)` Find the XA. `HBr//C_(6)H_(5)COOH`B. `Br_(2)//C Cl_(4)`C. `HBr`/peroxideD. `Br_(2)//H_(2)O` |
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Answer» Correct Answer - C |
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| 97. |
Statement-I: Alkenes participate in addition reaction Statement-II: Alkenes are unsaturated hydrocarbonsA. S-I & II are correct, S-II is correct explanation of S-IB. S-I&II are correct, S-II is not correct explanation of S-IC. S-I is true, but S-II is false.D. S-I is false, ut S-II is true |
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Answer» Correct Answer - A |
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| 98. |
Which of the following hydrogen halides is the most difficult to add to the double bond of alkenes ?A. `HI`B. `HBr`C. `HCl`D. `HF` |
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Answer» Correct Answer - D During addition, hydrogen halide provides a proton `(H^(+))` as an electrophile. Thus, the order of reactively is related to the order of acid strength: `HI gt HBr gt HCl gt HF` `HI` being the most acidic is the most reactive. Moreover, `I^(-)` is the strongest nucleophile while `F^(-)` is the weakest nucleophile. |
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| 99. |
Various strong bases have been used for dehydrohalogenation. Ptassium hydroxide dissolved in ethanol is a reagent sometimes used, but the sodium salts of alcohols, such as (and potassium) alkoxides are usually prepared by treating an excess of the alcohol withA. `NaOH`B. `NaH`C. `Na`D. Both (2) and (3) |
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Answer» Correct Answer - D `underset("Alcohol")(2ROH)+2Nararrunderset("alkoxide")underset("Sodium")(2RO^(-)Na^(+))+H_(2)` `underset("acid")underset("Stronger")(ROH)+2Na^(+)H^(-)rarrRO^(-)Na^(+)+underset("acid")underset("Weaker")(H-H)` `underset("acis")underset("Weaker")(ROH)+NaOHrarrRO^(-)Na^(+)+underset("acid")underset("Stronger")(H_(2)O)` Third reaction is not successful beacuse weaker acid cannot displace stronger acid. The excess alcohol becomes the solvent for the reaction. |
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| 100. |
On reductive ozonolysis, ethylene givesA. AldehydeB. KetoneC. Carboxylic acidD. Ether |
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Answer» Correct Answer - A |
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