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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.
| 351. |
In which of the following molecules `pi`-electron density in ring is maximum?A. B. C. D. |
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Answer» Correct Answer - B `overset(Ɵ)O` is better donar than `-NH_(2)` and `_OCH_(3)` |
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| 352. |
`underset((I))CH_(3)=Oharr ""^(o+)underset((II))CH_(2)-O^(Ө)harr""^(Ө)underset((III))CH_(2)` Which of these structues is practically not a valid canonical structure for formaldeyde?nA. (I)B. (II)C. (III)D. none of these |
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Answer» Correct Answer - C `overset(Ө)CH_(2)-underset(* *)overset(o+)O:` is highly unstable. (due to incomplete octet of oxygen ). |
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| 353. |
In which of the following molecules pi-electron density in ring is mininmum ?A. B. C. D. |
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Answer» Correct Answer - D Both `-NO_(2)` groups are `(-M)` in nature. So, they withdraw `e^(-)` from aromatic ring. |
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| 354. |
Among these compounds the correct order of C-N bond length is :A. `IVgtIgtIIgtIII`B. `IIIgtIgtIIgtIV`C. `IIIgtIIgtIgtIV`D. `IIIgtIgtIVgtII` |
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Answer» Correct Answer - C C-N bond in (III) is pure single bond so bond length is maximum. C-N bond in (IV) is pure double bond while in case of (I) and (II) resonance occur so single bond get converted in double bond. |
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| 355. |
Which is incorrect canonical structureA. IB. IIC. IIID. IV |
| Answer» Correct Answer - B | |
| 356. |
Correct order for resonance energy in the following molecules. A. III>I>IIB. III=I=IIC. IIIltIltIID. III=IgtII |
| Answer» Correct Answer - A | |
| 357. |
Which is/are the correct order of electron density in aromatic ring ?A. B. C. D. |
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Answer» Correct Answer - A::B::C::D On the basis of electronic effect. |
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| 358. |
Select the correct statement about this compound. A. All three `C-N` bond length are same.B. `C_(1)-N` and `C_(3)-N` bonds length are same but shorter than `C_(5)-N` bond length.C. `C_(1)-N` and `C_(5)-N` bonds length are same but longer than `C_(3)-N` bond length.D. `C_(1)-N` and `C_(3)-N` bonds length are different but both are longer than `C_(5)-N` bond length. |
| Answer» Correct Answer - C | |
| 359. |
Which of the following order is correct for heat of hydrogenation of these compounds? A. `XgtYgtZ`B. `ZgtYgtX`C. `YgtZgtX`D. `ZgtXgtY` |
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Answer» Correct Answer - A No of carbon `prop(1)/(HOH)` |
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| 360. |
Which of the following carbanions is the most reactive?A. `overset(-):CH_(3)`B. `CH_(3)overset(-)overset(..)CH_(2)`C. `(CH_(3))_(2)overset(-)overset(..)CH`D. `(CH_(3))_(3)overset(-)overset(..)C` |
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Answer» Correct Answer - D The order of reactivity of carbanion is the reverse of the order of stability: `3^(@)gt 2^(@) gt 1^(@)gt overset(-)overset(..)CH_(3)` |
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| 361. |
Resonance energy will be more ifA. canonical structures are equivalent than if canonical structures are non-equivalent.B. Molecule is aromatic than if molecule is not aromatic.C. more number of `pi`-bonds are involved in resonance than less number of `pi`-bonds are involved.D. Resonance with `2p-2p` overlapping than resonance with 3p-2p overlapping. |
| Answer» Correct Answer - A::B::C::D | |
| 362. |
The least acidic among the following acids is-A. Trrichloroacetic acidB. Dichloroacetic acidC. Monochloroacetic acidD. Acetic acid |
| Answer» Correct Answer - D | |
| 363. |
Homolytic fission of organic compound yieldsA. NucleophileB. CarbanionC. Free radicalD. Carbocation |
| Answer» Correct Answer - C | |
| 364. |
Cycloalkane has the formulaA. `C_(n)H_(2n+1)`B. `C_(n)H_(2n-2)`C. `C_(n)H_(2n)`D. `C_(2n)H_(2)` |
| Answer» Correct Answer - C | |
| 365. |
Among the following which one is most basic-A. `NH_(3)`B. `CH_(3)NH_(2)`C. `CH_(3)CH_(2)NH_(2)`D. `underset(Cl)underset(|)(C)H_(2)-NH_(2)` |
| Answer» Correct Answer - C | |
| 366. |
Consider the following compound IUPAC name of this compound isA. 5, 6-diethyl-3-methyl decaneB. 5, 6-diethyl-3-methyl dec-4-eneC. 3, 5, 6-trimethyl-dec-6-eneD. 3, 5,6-triethyl-dec-4-ene |
| Answer» Correct Answer - B | |
| 367. |
Name the alkene with molecular formula `C_(10)H_(20)`A. DodeceneB. UndeceneC. DeceneD. Heptene |
| Answer» Correct Answer - C | |
| 368. |
Which of the following is not a free radical ?A. `CI^(dot)`B. `(C_(6)H_(5))_(2)dotCH`C. `: C CI_(2)`D. `(CH_(3))_(2)dotCH` |
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Answer» Correct Answer - C Dichlorocarbene `(:CCI_(2))` is an electrophile |
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| 369. |
A free radical is a chemical species which isA. electron dificient and electrically neutralB. electron dificient and positively chargedC. electron rich and negatively chargedD. electron rich and electrically neutral |
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Answer» Correct Answer - A It is electron deficient the octet of the central `C` atom is not complete. It is electrically neutral because the central `C` atom has not lost any electron. |
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| 370. |
Which one is the characteristic feature of a free radical:A. presence of positive charge presence of unpaired electronB. presence of even number of electronsC. associated with high stabilityD. presence of odd no. of electrons |
| Answer» Correct Answer - d | |
| 371. |
Which alkenol is stable ?A. `CH_(2)=CH-CH_(2)-OH`B. `CH_(2)=CHOH`C. `CH_(3)-underset(CH_(3))underset(|)C=CH-OH`D. All of these |
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Answer» Correct Answer - B::C are enols and will tautomerise into `CH_(3)-undersetOunderset(||)C-H` and `CH_(3)-underset(CH_(3))underset|CH-CHO` respectively |
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| 372. |
Benzoylperoxide, when heated to about `80^(@)`C gives a-A. Free radicalB. CarbanionC. CarbocationD. none of these |
| Answer» Correct Answer - A | |
| 373. |
`CH_(3)CH_(2)Cl` undergoes homolytic fission, producesA. `CH_(3)overset(*)(C)H_(2)` and `overset(*)(C)l`B. `CH_(3)overset(o+)(C)H_(2)` and `Cl^(Θ)`C. `CH_(3)overset(o+)(C)H_(2)` and `overset(*)(C)l`D. `CH_(3)overset(*)(C)H_(2)` and `Cl^(Θ)` |
| Answer» Correct Answer - A | |
| 374. |
`CH_(3)CH_(2)Cl` undergoes homolytic fission to produceA. `CH_(3)dotCH_(2)` and `dotCI`B. `CH_(3)oversetoplusCH_(2)and CI^(-)`C. `CH_(3)oversetoplusCH_(2)and dotCI`D. `CH_(3)dotCH_(2) and CI^(-)` |
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Answer» Correct Answer - A In homolysis the covalent bond is broken in such a way that each resulting species known as free radical `CH_(3)-CH-CIoverset(Homolytic)underset(fusion)rarrCH_(3)dotCH_(3)+dotCI` |
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| 375. |
With the help of `F.C`. Explain which Lewis structure is more stable for the following molecules : (a) `N_(2)O: (i) :^(Theta)ddotN =overset(2+)O=ddotN:^(Theta) or (ii) :N -=overset(o+)N-ddotunderset(..)O:^(Theta)` (b). `H_(2)SO_(4): (i) H-O-overset( :ddotO:^(Theta))overset(|)underset(Theta)underset( :underset(..)O: )underset(|)(S^(+2))-O-H or (ii) H-O-underset( underset(..):O)underset(||)overset(ddotO: )overset(||)S-O-H` `HNO_(3)(i) H-O-underset(Theta)underset( :underset(..)O: )underset(|)overset(o+)N=ddotO: or (ii) H-O-underset(underset(..):O:_(Theta))underset(|)overset(+2)N-underset(..)ddotO:^(Theta)` (d). `CI_(2)O: (i) underset(..):ddotCI-ddotunderset(..)O-underset(..)ddotCI: or (ii) :underset(..)ddotO-underset(..)ddot(CI)-underset(..)ddotCI:` |
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Answer» (a) Structure (ii) is more stable, as it has less `F.C`. The central `N` has an `F.C` of `+ 1` and `O` has an `F.C` of `-1` But in structure (i), both `N` atoms have `F.C` of `- 1` and `O` has `F.C` of `+2`. (b) Structure (ii) is more stable, as it has no `F.C`, whereas structure (i) has `F.C` of `+2` on `S` and `F.C` of `-1` on each `O`. `S` has `d` orbitals, so it can expand its octet to have more than eight `overline e^, s`. ( c) Structure (i) is more stable, as it has less `F.C`. than structure (ii). Moreover, structure (ii) is not possible, because `N` has no `d` orbitals, so it cannot expand its octet and is limited to an octet. (d) Structure (i) is more stable, as it has no `F.C`., whereas structure (ii) has `F.C`. of `-1` on `O` and of `+ 1` on central `C 1`. `F.C`, in (i) : `F.C` on each `C 1= [7 - 6 - (1)/(2) (2)] = 0` `F.C on O = [6 - 4 - (1)/(2)(4)] = 0` `F.C` in (ii) `F.C` on `O = [6 - 6 - (1)/(2)(2)] = -1` `F.C` on central `C 1 = [7 - 4 - (1)/(2)(4)] = + 1` `F.C` on terminal `C1 = [7-6- (1)/(2)(2)] = 0`. |
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| 376. |
Which one is a `1^(@)` carbocation of the followingA. `CH_(3)overset(+)(C)H_(2)`B. `CH_(3)overset(+)(C)H-C_(2)H_(5)`C. `(CH_(3))_(2)overset(+)(C)H`D. `(CH_(3))_(3)overset(+)(C)` |
| Answer» Correct Answer - A | |
| 377. |
Homolytic fission of carbon-carbon bond of ethane produces an intermediate in which the carbon atom is inA. `sp^(2)` hybridized stateB. `sp^(3)`hybridized stateC. `sp` hybridized stateD. `dsp^(2)` hybridized state |
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Answer» Correct Answer - A `CH_(3)CH_(3)rarr 2CH_(3)` Hybridization of `C` atom in methyl free radical is `sp^(2)`. |
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| 378. |
In which of the following resonance is not possible ?A. `CH_(2)=C=CH_(2)`B. `CH_(2)=C=CH^(Theta)`C. `CH_(2)=C=CH^(o+)`D. `CH_(2)=C=CH^(*)` |
| Answer» Correct Answer - A | |
| 379. |
Which of the following has highest nucleophilicity ?A. `F^(-)`B. `OH^(-)`C. `CH_(3)^(-)`D. `NH_(2)^(-)` |
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Answer» Correct Answer - C Nucleophilicity is directly related to the basic strength if nucleophilic atoms belong to the same period of the periodic table. Order of basic strength of conjugates acids: `HF gt H_(2)O gt NH_(3) gt CH_(4)` Order of basic sterngth of conjugate bases: `CH_(3)^(-) gt NH_(2)^(-)gt OH^(-) gtF^(-)` Thus, order of nucleophilicity is as follows: `CH_(3)^(-) gt NH_(2)^(-) gt OH^(-) gt F^(-)` |
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| 380. |
`overset(Theta)(C)H_(3)` is less stable thanA. `CH_(3)-overset(Theta)(C)H_(2)`B. `CH_(3)-overset(Theta)(C)H-CH_(3)`C. `overset(Theta)(C)H_(2)-NO_(2)`D. `CH_(3)-overset(Theta)(C)H-C_(2)H_(5)` |
| Answer» Correct Answer - C | |
| 381. |
Which of the following atoms/groups exerts `-I` effect when attached to a carbon atom?A. `-NH_(2)`B. `-F`C. `-NO_(2)`D. all of these |
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Answer» Correct Answer - D The inductive effect of a substituent affects the charge or electron density on `C` Electronegative groups such as halogens tend to withdraw electron density from `C` whereas electropositive groups such as alkyl groups tend to increase its electron density. The effect is transmitted through the chain of `sigma` bonds and diminished with increasing chain length. All these substituents exert`-I` effect as they are more electronegative than the `H` atom. |
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| 382. |
Which of the following is the strongest nucleophile?A. `OH^(-)`B. `CH_(3)OH`C. `CH_(3)S^(-)`D. `CH_(3)O^(-)` |
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Answer» Correct Answer - C If nucleophilic atoms are the same, then nucleophilicity is directly related to basicity: `CH_(3)O^(-) gt OH^(-)gt CH_(3)OH` as `CH_(3)OH` is the weakest acid while `CH_(3)overset(+)OH_(2)` is the strongest acid. If nucleophilic atoms belong to the same group then nucleophilicity is inversely related to basicity: `CH_(3)S^(-) gt CH_(3)O^(-)` as `CH_(3)SH` is a stronger acid than `CH_(3)OH`. |
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| 383. |
Which of the following alkyl groups has the maximum `+I` effect?A. `CH_(3)-`B. `(CH_(3))_(2)CH-`C. `(CH_(3))_(3)C-`D. `CH_(3)CH_(2)-` |
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Answer» Correct Answer - C Increasing +I effect `(CH_(3))_(3)C gt (CH_(3))_(2)CH gt CH_(3)CH_(2) gt CH_(3)` |
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| 384. |
Which of the following alkyl groups has the maximum `+I` effect?A. `-CH_(3)`B. `CH_(3)-CH_(2)-`C. `(CH_(3))_(2)CH-`D. `(CH_(3))_(3)C-` |
| Answer» Correct Answer - D | |
| 385. |
An isomer of ethanol isA. MethanolB. Diethyl etherC. AcetoneD. Dimethyl ether |
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Answer» Correct Answer - D Ethanol is the functional isomer of dimethyl ether as both has same molecular formula. `underset("ethanol")(C_(2)H_(5)OH)(C_(2)H_(6)O)` and `underset("dimethyl ether")(CH_(3)-O-CH_(3)) " " (C_(2)H_(6)O)` |
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| 386. |
Polarization of electrons in acrolein may be written as:A. `overset(delta^(+))(C)H_(2)=CH-CH=overset(delta)(O)`B. `overset(delta^(+))(C)H_(2)=CH-overset(delta^(-))(C)H=0`C. `overset(delta^(-))(C)H_(2)=overset(delta^(+))(C)H-CH=0`D. `overset(delta^(-))(C)H_(2)=CH-CH=overset(delta^(+))(O)` |
| Answer» Correct Answer - A | |
| 387. |
Which is the decreasing order of stability (a). `CH_(3)-overset(+)(C)H-CH_(3)` (b). `CH_(3)-overset(+)(C)H-O-CH_(3)` (c). `CH_(3)_overset(+)(C)H-CO-CH_(3)`A. agtcgtbB. agtbgtcC. cgtbgtaD. bgtagtc |
| Answer» Correct Answer - D | |
| 388. |
Resonance is not possible in:A. B. C. `CH_(2)=CH-Cl`D. |
| Answer» Correct Answer - A | |
| 389. |
Which of the following species cannot show resonance?A. B. C. D. |
| Answer» Correct Answer - A | |
| 390. |
Which of the following is/are correct statement :A. B. C. D. |
| Answer» Correct Answer - A::D | |
| 391. |
Which of the following resonating structures of `1-`methoxy-`1`,`3`-butadiene is least stable?A. `CH_(2)=CH-overset(-)CH-overset(+)CH-overset(..)underset(..)CH_(3)`B. `overset(-):CH_(2)-CH=CH-CH=overset(+)underset(..)O-CH_(3)`C. `CH_(2)=CH-overset(-)overset(..)CH-CH=overset(+)underset(..)O-CH_(3)`D. `overset(-): CH_(2)=overset(+)CH-CH=CH-overset(..)underset(..)O-CH_(3)` |
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Answer» Correct Answer - D In resonance structures (2) and (3), all of the atoms have completed their octets while in structure (1) and (4), all of the atoms do not have complete octets. However, in structure (1), the `+ve` charge on the `C` atom can be dispersed by the `+R` effect of `underset(..)overset(..)OCH_(3)` group. Therefore, structure (4) is the least stable. Also note that structures (2) and (3) have more number of covalent bond than (1) and (4). |
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| 392. |
Resonance is delocalisation of :A. `pi` electronsB. `sigma` electronsC. `sigma-pi` electronsD. None |
| Answer» Correct Answer - A | |
| 393. |
Which molecules I showing `pi`-electrons alternate to `pi`-electron conjugationA. B. `CH_(2)=CH-overset(o+)(C)H_(2)`C. `CH_(2)=CH-overset(o)(C)H_(2)`D. `CH_(2)=CH-overset(.)(C)H_(2)` |
| Answer» Correct Answer - A | |
| 394. |
At room temperature, the eclipsed and staggered forms of ethane can not be isolated becauseA. They interconvert rapidlyB. Both the conformers are equally stableC. The energy difference between the conformers is largeD. There is a large energy barrier of rotation about the `sigma` bond |
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Answer» Correct Answer - A In staggered and eclipsed conformation of ethane, the basic structure of the ethane molecule and its various bond angles and bond lengths remain same. Since the repulsion between the non-bonded hydrogen atoms on the two carbons are minimum in the staggered conformation, hence staggered conformation is more stable than the eclipsed conformation by about `12.55 kJ mol^(-1)`. Further since this energy barrier of `12.55 kJ mol^(-1)` is very small and can be easily met by the collisions of the molecules at room temperature, hence these two conformation of ethane are readily interconvertible and hence cannot be separated at room temperature. |
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| 395. |
Which one of the following compounds is not aromatic?A. B. C. D. |
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Answer» Correct Answer - C c has `sp^(3)` carbon. |
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| 396. |
Among the cyclic ions, the aromatic character is shown by :A. `P and S`B. `Q and S`C. `Q and R`D. `P,Q,R and S` |
| Answer» Correct Answer - C | |
| 397. |
The IUPAC name of the following compound A. 1-Chloro-2,4 - dinitro benzeneB. 2 - Chloro - 1, 4-dinitro benzeneC. 1, 3 - Dinitro - 2 - chloro benzeneD. 4 - Chloro -1, 3-dinitro benzene |
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Answer» Correct Answer - A |
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| 398. |
Stability order of given anions is : A. `I gt III gt II`B. `I gt II gt III`C. `III gt II gt I`D. `III gt I gt II` |
| Answer» Correct Answer - A | |
| 399. |
The decreasing order of nucleophilies among the nucleophie : A. `1,2,3,4`B. `4,3,2,1`C. `2,3,1,4`D. `3,2,1,4` |
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Answer» Correct Answer - D If the size of electron donating atom is nearly same then, Nucleophilicity `propunderset("Basicity of anion")overset(I)rarr` |
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| 400. |
Which of the following anions is resonance destabilized?A. B. C. D. |
| Answer» Correct Answer - C | |