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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.
| 601. |
A molecule is `R_(3)C-H`. If H is replaced by A `(R_(3)C-A)` and on doing so electron density on `R_(3)C` part increases, then A is :A. electron attracting, then A is :B. electron withdrawing groupC. electron repelling groupD. either of them. |
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Answer» Correct Answer - C `underset("Therefore A is + I effect group")underset()(R_(3)C-Hoverset(-H)underset(+A)rarrR_(3)" "overset(delta-)C-overset(delta+)A,)` |
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| 602. |
The names of some compounds are given. Which one not in the `IUPAC` system?A. `CH_(3)underset(OH)underset(|)CH-underset(CH_(3))underset(|)CH-CH_(3)" "("3-Methyl-2-butanol")`B. `CH_(3)-CequivC-CH(CH_(3))_(2)" "("4-Methyl-2-pentyne")`C. `CH_(3)-CH_(2)-overset(CH_(2))overset(||)C-overset(CH_(3))overset(|)CH-CH_(3)underset(("2-Ethyl-3-methylbut-1-ene"))`D. `underset(("3-Methyl-4-ethyl heptane"))underset()(CH_(3)-CH_(2)-CH_(2)-underset(CH_(2))underset(|)CH-underset(CH_(3)CH_(3))underset(|)(CH)-CH_(2)CH_(3))` |
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Answer» Correct Answer - D `underset("Its correct name is 4-Ethyl-3-methylheptane.")underset()(overset(7)CH_(3)-overset(6)CH_(2)-overset(5)CH_(2)-overset(4)underset(CH_(2)CH_(3))underset(|)(CH)-overset(3)underset(CH_(3))underset(|)(CH)-overset(2)CH_(2)-overset(1)CH_(3))` |
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| 603. |
Electrophilic reagents areA. Electron pair donorsB. Lewis acidsC. Odd electron moleculesD. None of the above |
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Answer» Correct Answer - B Electrophilic reagents are Lewis acids. |
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| 604. |
Which of the following statements is correct ?A. Allyl carbonium ion `(CH_(2)=CH-overset(+)CH_(2))` is more stable than propyl carbonium ionB. Propyl carbonium ion is more stable than the allyl carbanionC. Both are equally stableD. None of the above. |
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Answer» Correct Answer - B See A-Level Information. |
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| 605. |
Which of the following statements is correct ?A. `+I` group stabilizes a carbanionB. `+I` group stabilizes a carbocationC. `-I` group stabilizes a carbocationD. `-I` group destabilizes a carbanion. |
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Answer» Correct Answer - B `+ I` group stabilises carbocation due to dispersal of positive charge on the + I effect group also. |
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| 606. |
In the Newman projection formula of the lost stable staggered form of `n`-butane, which of the following reasons is the causes of its unstability?A. van der Waals strainB. Torsional strainC. Combination of bothD. None of these |
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Answer» Correct Answer - A Van der Waals strain |
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| 607. |
Pick out the most stable carbonium ion:A. `C_(6)H_(5)-overset(+)underset(C_(6)H_(5))underset(|)C-C_(6)H_(5)`B. `CH_(3)-overset(+)underset(CH_(3))underset(|)C-CH_(3)`C. `CH_(3)-overset(+)CH-CH_(3)`D. `CH_(3)-CH_(2)-overset(+)CH_(3)` |
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Answer» Correct Answer - A Most stable carbocation is `underset("It is resonance stabilised.")underset()(C_(6)H_(5)-overset(+)underset(C_(6)H_(5))underset(|)C-C_(6)H_(5))` |
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| 608. |
Which of the following can act as an electrophile ?A. `CH_(3)overset(cdotcdot)underset(cdotcdot)O:^(-)`B. `:CH_(2)`C. `overset(cdotcdot)NH_(3)`D. None of these. |
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Answer» Correct Answer - B See A-Level Information. |
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| 609. |
Which of the following formula is most stable ?A. `CH_(3)-Cequivoverset(oplus)O:`B. `CH_(3)overset(+)C=overset(ddot)O:`C. `CH_(3)-overset(ddot)C=O^(+):`D. None of these |
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Answer» Correct Answer - A `CH_(3)-Cequivoverset(+)O:` is the most stable as the octet of each atom is complete. |
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| 610. |
The compound which gives the most stable carbonium ion on dehydration isA. `CH_(3)CH(CH_(3))CH_(2)OH`B. `(CH_(3))_(3)COH`C. `CH_(2)=CHCH_(2)CH_(2)OH`D. `CH_(3)CHOH.CH_(2).CH_(3)` |
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Answer» Correct Answer - B `(CH_(3))_(3)C-OH underset(-H_(2)O)overset(+H^(+))rarr (CH_(3))_(3)overset(+)(C)(3^(@)) ("more stable")`. `CH_(2)=CH-CH_(2)-CH_(2)OH underset(-H_(2)O)overset(+H^(+))rarr CH_(2)=CH-CH_(2)-overset(+)(C)H_(2)(1^(@)) ("less stable")` |
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| 611. |
Which one of the following molecules exists as a resonance hybrid ?A. B. `CH_(2)=CH-CH_(2).CHO`C. `CH_(2)=CH-CH_(2)OH`D. `CH_(2)=CH-NO_(2)`. |
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Answer» Correct Answer - D There is conjugation in `CH_(2)=CH-underset(darr)N=O` |
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| 612. |
Which of the following contains three pairs of electrons in the valence shell?A. CarbocationsB. CarbanionsC. free radicalsD. None. |
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Answer» Correct Answer - A A carbocation contains three pairs of electron in the valence shell. |
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| 613. |
Assertion: Paper chromatography is a type of partition chromatography. Reason: Moving phase is liquid and stationary phase is solid.A. If both assertion and reason are true and reason is the correct explanation of assertionB. If both assertion and reason are true but reason is not the correct explanation of assertionC. If assertion is true but reason is false.D. If both assertion and reason are false. |
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Answer» Correct Answer - C Chromatography paper contains water trapped in it, which acts as the stationary phase. Mobile phase is solvent or a mixture off solvents in which spotted chromatography paper is suspended. Thus, both mobile and stationary phase are liquids. |
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| 614. |
Which of the following species are planar ?A. Singlet carbeneB. Triphenyl methyl carbocationC. Isopropyl carbanionD. Nitromethyl carbanion. |
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Answer» Correct Answer - A::B::D A triphenyl methyl I carbocation, singlet carbene and nitromethylcarbanion are planar species as central carbon atom in each of them is `sp^(2)`- hybridised. In isopropyl carbanion, C is `sp^(3)`- hybridised and is pyramidal. The planar nature of nitromethyl carbanion can be explained on the basis of resonance. When the unshared pair of electrons on the carbon atom carrying -ve charge is conjugated with a multiple bond, then the carbene is always planar for resonance to occur. Another such example is allyl carbanion `(CH_(2)=CH-CH_(2)^(-)).` |
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| 615. |
An organic reaction occurs through making and breaking of bonds. The breaking of bonds may occur either homolytically leading to the formation of radicals or heterolytically generating positively and negatively charged species. The neutral species (free radicals, carbenes, nitrenes, etc.) and positively charged species being electron deifcient are collectively called electrophiles while neutral and negatively charged species which are electron rich are called nucleophiles. An organic reaction usually involves the attack of a reagent (radicals, positively and negatively charged species) on the substrate molecule). The substrate molecule, although as a whole electrically neutral, has centres of low and high electron density due to displacement of bonding electrons. These electrons displacements occur through inductive, electromeric occur through inductive, electromeric, resonance and hyperconjugation effects. Whereas inductive effects involve displacement transfer of n-and `pi`-electrons along a conjugated system. Hypercongation effects, on the other hand, involve `sigma-pi`-conjugation. Both inductive and hyperconjugation effects can be used to explain the stability of carbocations and free radicals which follow the stability order: `3^(@) gt 2^(@) gt 1^(@)`. The stability of carbanions, however, follows opposite order. The stability of a molecule can be judged on the basis of contribution of its resonance structures. Resonance structures have same position of nuclei and have same number of unpaired electrons. Among resonance structures, the one which has greater number of covalent bonds, has less separation of opposite Charges, a negative charge on more electronegative and a positive charge on a more electropostive atom are more stable than others. Which of the following series contains only electrophiles ?A. `H_(2)O, SO_(3), H_(3)O^(+)`B. `NH_(3), H_(2)O, AlCl_(3)`C. `AlCl_(3), SO_(3), overset(+)(N)O_(2)`D. `H_(2)O, overset(+)(C)l, NH_(3)` |
| Answer» Correct Answer - C | |
| 616. |
An organic reaction occurs through making and breaking of bonds. The breaking of bonds may occur either homolytically leading to the formation of radicals or heterolytically generating positively and negatively charged species. The neutral species (free radicals, carbenes, nitrenes, etc.) and positively charged species being electron deifcient are collectively called electrophiles while neutral and negatively charged species which are electron rich are called nucleophiles. An organic reaction usually involves the attack of a reagent (radicals, positively and negatively charged species) on the substrate molecule). The substrate molecule, although as a whole electrically neutral, has centres of low and high electron density due to displacement of bonding electrons. These electrons displacements occur through inductive, electromeric occur through inductive, electromeric, resonance and hyperconjugation effects. Whereas inductive effects involve displacement transfer of n-and `pi`-electrons along a conjugated system. Hypercongation effects, on the other hand, involve `sigma-pi`-conjugation. Both inductive and hyperconjugation effects can be used to explain the stability of carbocations and free radicals which follow the stability order: `3^(@) gt 2^(@) gt 1^(@)`. The stability of carbanions, however, follows opposite order. The stability of a molecule can be judged on the basis of contribution of its resonance structures. Resonance structures have same position of nuclei and have same number of unpaired electrons. Among resonance structures, the one which has greater number of covalent bonds, has less separation of opposite Charges, a negative charge on more electronegative and a positive charge on a more electropostive atom are more stable than others. For 1-methoxy-1, 3-butadiene, which of the following resonating structure is the least stable ?A. `H_(2)overset(-)(C)-overset(+)(C)H-CH=CH-O-CH_(3)`B. `H_(2)overset(-)(C)-CH=CH-CH=overset(+)(O)-CH_(3)`C. `H_(2)C = CH-overset(+)(C)H-overset(-)(C)H-O-CH_(3)`D. `H_(2)C=CH-overset(-)(C)H-CH=overset(+)(O)-CH_(3)` |
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Answer» Correct Answer - C All the atoms in structures (b) and (d) have complecyed octets and hence are more stable than structure (a) and (c) in which the positively charged carbon has only sextet of electrons. Out of (a) and (c), (a) is stabilized by +R-effect of the oxygen atom but (c) is not. Thus, (c) is th least stable structure. |
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| 617. |
Which of the following species is/are planar ?A. tert-Butyl free radicalB. tert-Butyl carbocationC. tert-Butyl carbanionD. Allyl carbanion |
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Answer» Correct Answer - A::B::D Allyl carbanion due to resonance is planar, tert-Butyl free radical and tert-butyl carbocation are also planar but tert-butyl carbanion is pyramidal. |
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| 618. |
Which of the following behave both as a nucleophile as well as an electrophile ?A. `CH_(3)OH`B. `CH_(3)Cl`C. `CH_(3)CN`D. HCHO |
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Answer» Correct Answer - C::D `CH_(3)C-=N` and `H_(2)C = O` both act as nucleophiles due to the presence of lone pair/s of electrons on oxygen or nitrogens and electrophiles due to the presence of multiple bonds. |
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| 619. |
Statement-1: Bridge head carbocation is less stable than Bridge head carbanion. and Statement-2: C atom in carbocation is `sp^(2)` generally hybridized. |
| Answer» Correct Answer - B | |
| 620. |
The decreasing order of electronegativity of the hybrid orbitals is :A. `spgtsp^(2)gtsp^(3)`B. `sp^(3)sp^(2)gtsp`C. `sp^(2)gtsp^(3)gtsp`D. `sp^(2)gtspgtsp^(3)` |
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Answer» Correct Answer - A See classification of organic compounds. |
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| 621. |
0.395 g of an organic compound by carius method for the estimation of sulphur gave 0.582 g of `BaSO_(4)`. Calculate the percentage of sulphur in the compound. |
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Answer» Correct Answer - `20.24` Percentage of sulphur `=32/233xx("Mass of "BaSO_(4))/("Mass of compound")xx100=32/233xx0.582/0.395xx100=20.24 %` |
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| 622. |
0.2174 g of the substance gave 0.5825 g of `BaSO_(4)` by Carius method. Calculate the percentage of sulphur. |
| Answer» Correct Answer - `36.78%` | |
| 623. |
0.2595 g of an organic substance, when treated by Carius method, gave 0.25 g of `BaSO_(4)`. Calculate the percentage of sulphur in the compound. |
| Answer» Correct Answer - `13.23%` | |
| 624. |
How many intermediates are obtained when reactant is treated with an electrophile `E^(+)`? |
| Answer» Correct Answer - 5 | |
| 625. |
Statement-1: When is treated with excess of `Ag^(+)` ion. One mole of the compound reacts with four moles of `Ag^(+)` and Statement-2: `Ag^(+)` is a Lewis acid hence it reacts with `Br^(-)` ion on which is a Lewis base. |
| Answer» Correct Answer - D | |
| 626. |
On how many atoms positive charge is deloclized in the given ion ? |
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Answer» Correct Answer - 4 |
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| 627. |
Statement-1: In naphthalene all C-C bonds are equal and Statement-2: Like benzene naphthalene is also aromatic. |
| Answer» Correct Answer - D | |
| 628. |
Statement-1: p-Nitroaniline is more polar than nitrobenzene and Statement-2: Nitro group has -M effect. |
| Answer» Correct Answer - B | |
| 629. |
I. `CH_(3) - CH_(2) - CH_(2) - CH_(2) - OH` II. `CH_(3) - CH_(2) - underset(OH)underset(|)(CH) - CH_(3)` III. `CH_(3) - underset(OH) underset(|)overset(CH_(3))overset(|)(C) - CH_(3)` IV. `CH_(3) - underset(CH_(3))underset(|)(CH) - CH_(2) - OH` V. `CH_(3) - CH_(2) - O - CH_(2) - CH_(3)` VI. `CH_(3) - O - CH_(2) - CH_(2) - CH_(3)` VII. `CH_(3) - O - underset(CH_(3))underset(|)(CH) - CH_(3)` Identify the pairs of compounds that represents position isomerism. |
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Answer» When two or more compounds differ in position of substituent atom or functional groups on the carbon skeleton, they are position isomers. In the given structure I and II, III and IV, and VI and VII are position isomers. I. `underset(1-"butanol")(CH_(3) - CH_(2) - CH_(2) - CH_(2) -OH)` II. `underset(2-"butanol")(CH_(3) - CH_(2) - underset(OH)underset(|)(CH) - CH_(3))` III. `underset(2-"methyl propanol"-2)(CH_(3) - underset(OH)underset(|)overset(CH_(3)) overset(|)(C) - CH_(3))` IV. `underset(2-"methyl propanol"-1)(CH_(3) - underset(CH_(3)) underset(|)(CH) - CH_(2) - OH)` VI. `underset("Methoxy propane")(CH_(3) - O - CH_(2) - CH_(2) - CH_(3))` and VII. `underset(underset("methoxy 1-methyl ethane")("Methoxy isopropane or"))(CH_(3) - O - underset(CH_(3))underset(|)(CH) - CH_(3))` |
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| 630. |
Which of the following represents the correct order of stability of the given carbocations ? A. `IIIgtIgtII`B. `IgtIIIgtII`C. `IIIgtIIgtI`D. `IIgtIIIgtI` |
| Answer» Correct Answer - A | |
| 631. |
Which of the following represents the correct order of stability of carbocations ?A. `(CH_(3))_(3)overset(+)CgtCH_(2)=CHoverset(+)CH_(2)gtC_(6)H_(5)overset(+)CH_(2)gt(CH_(3))_(2)overset(+)CH`B. `C_(6)H_(5)overset(+)CH_(2)gtCH_(2)=CH-overset(+)CH_(2)gt(CH_(3))_(3)overset(+)Cgt(CH_(3))_(2)overset(+)CH`C. `CH_(2)=CHoverset(+)CH_(2)gtC_(6)H_(5)overset(+)CH_(2)gt(CH_(3))_(2)overset(+)Cgt(CH_(3))_(2)overset(+)CH`D. `(CH_(3))_(3)overset(+)CgtC_(6)H_(5)overset(+)CH_(2)gt(CH_(3))_(2)overset(+)CHgt(CH_(3))_(2)overset(+)CH` |
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Answer» Correct Answer - D Correct order of stability is `(CH_(3))_(3)overset(+)CgtC_(6)H_(5)overset(+)CH_(2)gt(CH_(3))_(2)overset(+)CHgtCH_(2)=CH-overset(+)CH_(2)` |
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| 632. |
In which of the following molecules, the substituent does not exertis resonance effect ?A. `C_(6)H_(5)NH_(2)`B. `C_(6)H_(5)overset(+)NH_(3)`C. `C_(6)H_(5)OH`D. `C_(6)H_(5)Cl` |
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Answer» Correct Answer - B In `C_(6)H_(5)overset(+)NH_(3),` the substituent does not exert its resonance effect. It is due to the absence of lone pair of electrons on N. |
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| 633. |
The lowest alkane which has ethyl group is substituent has IUPAC nameA. 2-EthylpropaneB. 2-EthylbutaneC. 3-EthylpentaneD. None of these |
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Answer» Correct Answer - C `underset("4-Ethylheptane")underset()(overset(7)CH_(3)-overset(6)CH_(2)-overset(5)CH_(2)-overset(CH_(2)-CH_(3))overset(4|)(CH)-overset(3)CH_(2)-overset(2)CH_(2)-overset(1)CH_(3))` |
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