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.
| 351. |
The stable conformer `(s)` of cis-cyclohexane `1-3-` diol is/are:A. `1-` axial`-3-` axial formB. `1-` axial`-3-` equatorial formC. `1`-equatorial- `3`- axial formD. `1`- equatorial -`3`- equatorial form |
| Answer» Correct Answer - A | |
| 352. |
How many chiral centers are present in tetracyline? A. 6B. 4C. 8D. 5 |
| Answer» Correct Answer - D | |
| 353. |
R,S-configuration is a useful tool for determination of enantiomers, diasteromers and homomers. If configuration of all chiral centers are opposite then structures are enantiomers, if all chiral centers have same configuration then they are homomers and if some have same confguration and some have opposite configuration then they are diastereomers. Find out homomers:A. I and IIIB. II and IVC. I and IVD. III and IV |
| Answer» Correct Answer - C | |
| 354. |
A pair of enantiomers is :A. a pair of non superimposable mirror image of each otherB. a pair of superimposable image of each otherC. always optically active if one is dextrorotatory then other will be leavorotatory by same magnitudeD. compounds having same boiling points |
| Answer» Correct Answer - A::C::D | |
| 355. |
Tell whether the two structrues in each pair represent enantiomers or two molecules of the same compound in different orientions. |
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Answer» a. Enantiomers b. Enanitomers c. Two molecules of the same compound. |
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| 356. |
Wich of the following paris of compounds is pair of enantiomersA. B. C. D. |
| Answer» Correct Answer - B | |
| 357. |
Which of the following structures repersent meso compoundA. B. C. D. |
| Answer» Correct Answer - B | |
| 358. |
Which of the following paris of structures does not repersent isomers ?A. B. C. D. |
| Answer» Correct Answer - D | |
| 359. |
Which of the following paris of structires does not repersent tautomers ?A. B. C. D. |
| Answer» Correct Answer - B | |
| 360. |
The following structures repersent a pair of : A. enantiomersB. diastereomersC. meso compoundD. homomer |
| Answer» Correct Answer - D | |
| 361. |
Which of the following statements regarding the concept of resonance is not correct?A. The different resonating structrue of a molecule have fixed arrangement of atomic nucleiB. The different resonating structrues differ in the arrangement of electrons.C. None of the individual resonating structrue explains the various characterstics of the molecule.D. The hybrid structrue have equal contribution from all the resonating structrues. |
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Answer» Correct Answer - D Statement `(d)` is wrong because resonating structures have different stabilities and, therefore, their contributions to the hybrid structrue are different. |
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| 362. |
`Ph-underset((A))underset(OH)underset(|)CH-overset(O)overset(||)C-Hunderset(H_(2)O)overset(HO^(ɵ))rarr` (A) and (B) are isomer and isomerization effectively carried out by treace of base (B). Identify (B).A. `Ph-CH_(2)-overset(O)overset(||)C-O-H`B. `Ph-overset(O)overset(||)C-O-CH_(3)`C. `Ph-overset(O)overset(||)C-CH_(2)-OH`D. `H-overset(O)overset(||)C-CH_(2)-O-Ph` |
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Answer» Correct Answer - c Enal from of (A) is `Ph-underset(OH)underset(|)C=CH-OHoverset("Tautomerises")hArrPh-underset(O)underset(||)C-CH_(2)-OH` |
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| 363. |
Which of the given compound is optically active?A. B. C. D. |
| Answer» Correct Answer - b,c | |
| 364. |
Correct statement(s) is/are reagarding following compounds : A. All are geometrical isomer of each other.B. All are optical isomer of each other.C. All are configurational isomer of each other.D. Only two Q and R are resolvable. |
| Answer» Correct Answer - a,b,c,d, | |
| 365. |
`CH_(3)-underset(O)underset(||)(C)-overset(CH_(3))overset(|)(C)HCH_(3)` and `overset(CH_(3))overset(|)(C)H_(2)-underset(O)underset(||)(C)-CH_(2)CH_(3)` express which type isomerismA. metamersB. TautomersC. Functional isomersD. Position isomers |
| Answer» Correct Answer - A | |
| 366. |
which of the following conformations of -n- butane is least stabel ?A. GaucheB. AntiC. EclipsedD. Fully eclipsed |
| Answer» Correct Answer - D | |
| 367. |
Which of the following can exist in syn and anti form?A. `Ph-N=N-OH`B. `Ph-N=N-Ph`C. `Ph-CH=N-OH`D. `Ph_(2)C=N-OH` |
| Answer» Correct Answer - A::B::C | |
| 368. |
Which of the following statements are correct about these molecules?A. I is a meso compoundB. I and III are identicalC. II and IV are a pair of enantimoersD. II and III are diastereomers |
| Answer» Correct Answer - A::B::C::D | |
| 369. |
Which of the following compounds can have superimposable mirror image?A. B. C. D. |
| Answer» Correct Answer - A::B::C | |
| 370. |
Which of the following statements are true about these isomers?A. I and II are pair of enantiomersB. III and IV are a pair of enantiomersC. II is the diastereomer of III and IVD. I and III are homomers |
| Answer» Correct Answer - A::B::C | |
| 371. |
The Z-isomers among the following are:A. B. C. D. |
| Answer» Correct Answer - A::C | |
| 372. |
Isomers do not haveA. same number of atomsB. same kinds of atomsC. same molecular formulaD. same properties |
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Answer» Correct Answer - D The term "isomers" comes from the greek word meaning equal weights. They are different compounds having different properties on account of different structures and or shapes. |
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| 373. |
Consider the following structure and pich by the right statement : A. I and II have R-configurationB. I and II have R-configurationC. only III has S-configurationD. I and II have S-configuration |
| Answer» Correct Answer - A::C | |
| 374. |
Total stereoisomer for lt brgt are:A. 4B. 6C. 8D. 2 |
| Answer» Correct Answer - b | |
| 375. |
Which of the following will have least hindered rotation about carbon-carbon bond?A. EthaneB. EthyeneC. AcetylaneD. Hecachloroethane |
| Answer» Correct Answer - a | |
| 376. |
Which of the following will have the least hindered rotation about carbon-carbon bonds?A. EthaneB. EthyleneC. AcetyleneD. Hexachlorethane |
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Answer» Correct Answer - A Ethane `(CH_(3)-CH_(3))` has the least hindered rotation about `(C-C)` bond. |
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| 377. |
Among the following the Mnewmann projections of meso 2, 3 butanediol are A. P,QB. P,RC. R,SD. Q,S |
| Answer» Correct Answer - B | |
| 378. |
Which of the following statements best descries the stereochemical frlationships compound I,II and III shown below A. All compounds are chiralB. None of the compounds id chiralC. I and II meso compoundsD. I and II are chiral |
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Answer» Correct Answer - d `III^(rd)` compound has plane of symmetry so potically inactive but I and II are optically active and are chiral. I and II are enantiomers whereous III is a meso compound. |
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| 379. |
The compounds whose stereochemical formula is written below exhibits x geometrical isomers and y optical isomers. The values of x and y areA. 4 and 4B. 2 and 2C. 2 and 4D. 4 and 2 |
| Answer» Correct Answer - B | |
| 380. |
Conformations are different arragements of atoms htat are interconverted by rotation about single bond. IN eclipsed conformation, the `C-H` bond on one carbon is directly aligned with `C-H` bond on the adjacent carbon. In staggered conformation, the `C-H` bond on one carbon bisect the `H-C-H` bond angle on adjacent carbon. The angle that seperates a bond on one atom form a bond on a adjacent atom is called a dihedral angle. A staggered conformation with two larger groups `180^(@)` from each other is called anti. A staggered conformation with two larger group `60^(@)` from each other is called gauche Identify the most conformer of 2-fluoro ethanol among the following:A. B. C. D. |
| Answer» Correct Answer - C | |
| 381. |
Presence of chiral center is not an essential condition to show optical isomerism. Essential condition is, compound should show non-superimposable mirror image. Allenes do not contain chiral center but show optical isomerism when different groups are attached on double bonded carbonds. Biphenyls alos show optical isomerism when both rings are perpendicular to each other and any ring should not contain plane of symmetry. Which of the following compounds can be revolved in enantiomeric form ?A. B. C. D. |
| Answer» Correct Answer - C | |
| 382. |
Presence of chiral center is not an essential condition to show optical isomerism. Essential condition is, compound should show non-superimposable mirror image. Allenes do not contain chiral center but show optical isomerism when different groups are attached on double bonded carbonds. Biphenyls alos show optical isomerism when both rings are perpendicular to each other and any ring should not contain plane of symmetry. Which of the following biphenyl compounds is optically active?A. B. C. D. All are correct |
| Answer» Correct Answer - B | |
| 383. |
Identify the pairs of enantiomers and diastereomers from the following: |
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Answer» (I) and (II) are enantiomers, I and II, and II and III are diastereomers. |
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| 384. |
The configurations of the carbon atoms `C_(2)` and `C_(3)` in the following compound respectively A. R,SB. S,SC. R,SD. S,R |
| Answer» Correct Answer - a | |
| 385. |
The compound in which the distance between the two adjacent carbon atoms is largest is :A. EthaneB. EtheneC. EthyneD. Benzene |
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Answer» Correct Answer - A Bond length order: `{:(C-Cgt,C=Cgt,C-=C,,),(154,134,120p m,,):}` In benzene, due to resonance, the bond length lies in between single and double bond and is `139 p m`. |
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| 386. |
The compound which is not isomeric with diethyl ether is :A. `n`- Propyl methyl etherB. Butan-`1-ol`C. `2`- Methyl propan-`2-ol`D. Butanone |
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Answer» Correct Answer - D Ethers and alcohols are functional isomers, so butanone (ketone) is not isomeric with diethylether. |
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| 387. |
Which of the following hydrocarbons has the lowest dipole moment?A. B. `CH_(3)C-=C CH_(3)`C. `CH_(3)CH_(2)C-=CH`D. `CH_(2)=CH-C-=CH` |
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Answer» Correct Answer - B `CH_(3)C-=C CH_(3)` is linear and symmetrical and thus dipole moment in zero. |
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| 388. |
The optical rotation of an optically active compound is `+20^(@)`. The length of tube is `10 cm` and the density of solution is `0.4 gm ml^(-)`. The specific rotation of the compound is: i. `+50^(@)` ii. `+500^(@)` iii. `+5^(@)` iv. `+0.5^(@)` b. Which of the following are optically active compounds and why? i. Butan-1-ol ii. 2-Chlorobutane II. Lactive acid iv. 3-Chloropentane c. Which of the following are optically active and why? i. `CH_(3)CH(Cl)CH_(3)` ii. `CH_(3)CH_(2)CH(CH_(3))COOH` iii. `CH_(3)CH_(2)CH(NH_(2))CH_(3)` iv. `CH_(2)OHCH_(2)OH` d. Which of the following are optically active and why? i. Propan-1-ol , ii. Butan-2-ol iii. Heptan-4-ol , iv. 3-Aminohexane v. 2-Chloropentane , vi. 2,2-Dichloropropane e. Mark `(**)` on the asymmetric carbon atom, if any, in the following compounds: (i) `CH_(3)-CHCl-CH_(2)-CH_(3)`, ii. `CH_(3)-CHOH-CH_(3)`. |
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Answer» a. i. `10cm=1 dm, [alpha]=(+120^(@))/(1xx0.4)= +50^(@)` b. The structural formulas of the given compounds are as under : (i). `CH_(3)CH_(2)CH_(2)CH_(2)OH` (Butan-1-ol) Butan-1-ol is not optically acive since it does not contain any asymmetric carbon atom. Hence the molecule is achiral. ii. `CH_(3)-.^(**)overset(Cl)overset(|)CH-CH_(2)-CH_(3)` (2-Chlorobutane) `2`-Chlorobutane is a chiral molecule since it contains an asymmetric carbon atom marked with an asterisk. Hence, it is optically active. iii. `CH_(3)-.^(**)overset(OH)overset(|)CH-CH_(2)-COOH` Lactic acid contains one asymmetric carbon atom and its molecule is chiral. Thus, it shows optical activity. iv. `CH_(3)CH_(2)-overset(OH)overset(|)CH-CH_(2)CH_(3)` (3-Chloropentane) `3`- Chloropentane is a symmetrical moleucle since it does not contain an asymmetric carbon atom. Hence it does not show optical activity. c. (ii) and (iii) have asymmetric `C` atom. d. (ii), (iv) and (v) have asymmetric `C` atom. e. i. has asymmetric `C` atom, `CH_(3)-overset(**)CH(Cl)-CH_(2)CH_(3)` |
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| 389. |
An aqueous solution containing `10 gm` of optically pure fructose was diluted to `500 ml` with water and placed in a polarimeter tube `20 cm` long. The measured roatation was `-5.0^(@)`. To this solution, `500 ml` of a solution containing `10 gm` of racemic fructose is added. What will be the change in specific rotation? |
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Answer» As we know, `20 cm= 2dm`. `[alpha]_(D)=(theta)/(lxxC)=(-5.0^(@))/(2dmxx10gm//500ml)=-125^(@)` Total volume of solution `=500+500= 1000 ml` Mass per ml of pure fructose`=10//1000` `= 0.01 gm m1^(-1)` Mass per `m1` of mixtrue `= (10 + 10 = 20) = 20//1000` `= 0.02 gm m1^(-1)` `OP` (optical purity) = `([alpha]_(obs.)"of mixtrue")/([alpha]_(D) "of pure form") prop("Mass per ml of pure form")/("Mass per ml of mixtrue")` `=(0.01)/(0.02)= 0.5( because l "constant")` New `[alpha]_(D)= -125^(@)xx0.5= -62.5^(@)` Change in specific rotation `=-62.5- (-125)= +62.5^(@)` |
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| 390. |
When 20 gm optically active compound is placed in a 10 dm tube, in a 200 ml solution rotates the PPL by `30^(@)` : (a) What is the angle of rotation if above solution is dilute to 1 litre ? (b) What is the specific angle of rotation if above solution is diluted to 1 litre ? |
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Answer» Correct Answer - 630 Mass = 20 gm Volume = 200 ml `C=(mass)/(volume)=20/200=0.1gm//ml` Length of tube (l) = 10 dm Optical rotation `theta=30^(@)` `" "alpha=(theta)/(Cxxl)` `" "alpha=30/(0.1xx10)=30` (a) If solution is dilute to one litre then volume V= 1000 ml `theta`=? `alpha=(theta)/(Cxxl),30=(theta)/(20/1000),theta=6^(@)` (b) Specific rotation does not change with change in conc. or volume of length etc. therefore it is `30^(@)` |
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| 391. |
Most stable conformation of n-pentane is : ( Consider `C_(2)-C_(3)` bond rotation )A. B. C. D. |
| Answer» Correct Answer - b | |
| 392. |
The most stable enolic from of 2, 4-pentanedione is :A. `CH_(2)=overset(OH)overset(|)(CH-CH_(2))-overset(O)overset(||)(C)-CH_(3)`B. `CH_(3)-overset(OH)overset(|)(C)=CH-overset(O)overset(||)(C)-CH_(3)`C. `CH_(2)=underset(OH)underset(|)(CH)-underset(OH)underset(|)(CH)=CH_(2)`D. `CH_(3)-underset(OH)underset(|)(C)=C=underset(OH)underset(|)(C)-CH_(3)` |
| Answer» Correct Answer - B | |
| 393. |
Give the correct order of initials T or F for following statements. Use T if statement is true and F if it is false : Me-CH=C=C=CH-Br is optically active. All optically active compound are chiral. All chiral pyramndal molecules are optically inactive. `{:(CH_(3)-CH_(2)-CH_(2)-COOH "and" CH_(3)-underset(COOH)underset(|)"CH"-CH_(3)` ),("are positional isomers."):}A. TTTFB. FTFTC. FTFFD. TFTT |
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Answer» Correct Answer - c (Q) Cycline chiral pyramidal molecules are optically active. (S) `CH_(3)-CH_(2)-CH_(2)-COOH` and `CH_(3)-underset(COOH)underset(|)CH-CH_(3)` |
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| 394. |
A naturally occurring substance has the constitution shown below. How many may haver this constitution ? A. 2B. 8C. 16D. 64 |
| Answer» Correct Answer - D | |
| 395. |
Match the following columns : |
| Answer» Correct Answer - a-q,r,s ; b-q ; c-p,r,s ; d-p,r,s,t | |
| 396. |
Match the following columns : |
| Answer» Correct Answer - a-s;b-r;c-q;d-s | |
| 397. |
Match the following columns : |
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Answer» Correct Answer - a-p,r ; b-q,t ; c-p,t ; d-q,r,s (p) Keto `gt` enol (stability) (q) Complete the octet more stable the resonating structure (r ) Aromatic enol `gt` jeti (stability) (s) More number of `alpha` H more will be the stability of alkene (t) Complete octet more stable resonationg structure |
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| 398. |
Which of the following statements are correct?A. diastereomers have different physical properties but not identical chemical properties.B. Enantiomers have the same physical and chemical properties but different physiological properties.C. Polarimeter is used in measuring the optical rotation of compund.D. Only organic molecules show optical isomerism. |
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Answer» Correct Answer - A::B::C d. Some coordination compounds show optical isomerism. |
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| 399. |
Which of the following will show optical activity?A. B. C. D. |
| Answer» Correct Answer - d | |
| 400. |
Which of the following will shown optical activity ?A. B. C. D. |
| Answer» Correct Answer - D | |