set of 50 obj in general organic chemistry by s.k.sinha

8/14/2019 Set of 50 obj in General Organic Chemistry by S.K.sinha http://www.openchemistry.in

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SINHA IIT CHEMISTRY TEST- G.O.C.

SCHOOL OF CHEMISTRY 1-D-10 Talwandi Commerce College Main Road Kota Ph -0744-2407906 1

Practice Test in G.O.C

1. Which of the following statement are correct ?Delocolisation of electron increase molecular stability because(a) electron nuclei attraction increases (b) electron electron repulsion increases(c) potential energy of the molecule increases (d) potential energy of the molecule decreases

2. Which of the following statements are incorrect about canonical structure? All canonical structures of a molecule(a) must have same number of unpaired electron(b) must have different number of unpaired electrons(c) need not be always equivalent but they should not differ much in stability(d) must have electrons in different orbital

3. Which of the following statements are true about resonance ?(a) Resonance involves delocolisation of & elements(b) Resonance involves delocolisation of electrons only(c) Resonance has no effect on potential energy of the molecule.(d) Resonance hybrid explains all feature of molecule

4. A canonical structure will be more stable if (a) If has more number of bonds than if it has less number of bonds.(b) the octet of all atoms are complete than if octet of all atoms are not complete.(c) it has charge separation than it has no charge separation(d) - ve charge is on more electronegative atom than if +ve charge in on less electronegative atom

5.. Which of the following pairs of structures are resonance structures:

(I)

CH 3 O

CH 3 C == N(CH 3)2 and

CH 3 O

H3C C N(CH 3)2

(II)

OH

OHHOand

OH

OHHO

(III)

N

H

O

and

OH

N

(IV)

O

(C6H

5)

2CH N

O

and(C

6H

5)

2C = N

OH

O

(a) I and IV (b) II and III (c) I and II (d) All

6.. Polarisation of electron in acrolein may be written

(a)CH 2 == CH CH == O

+ (b) CH 2 == CH CH == O +


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(c)CH 2 == CH CH == O

+ (d)CH 2 == CH CH == O

+

7. In which of the following lone pair indicated is not involved in resonance

(a) 2 2CH CH CH (b) 2CH =CH CH= N H

(c)

N

H

(d)

N

8. In which of the following lone pair indicated is not involved is resonance

(a) CH 2 = CH N H

CH 3 (b) CH 2 = CH CH = O

(c) CH 2 = CH O

CH = CH 2 (d)

O

9. Identify electron withdrawing groups in resonance among the following(a) CO 2H (b) C NH CH 3

O

(c) C Cl

O

(d) CN

10. Identify electron donating groups in resonance among the following(a) C NH 2

O(b) NO 2 (c) O C CH 3

O

(d) C OCH 3

O11. Which of the following groups cannot participate in resonance with other suitable groups?

(a) CO 2H (b) CO 2

(c) C Cl

O

(d) +

3N H

12. Which of the following groups can participate in resonance with other suitable groups?

(a) CH 2 =+

O (b) CH 2 2C H

(c) CH 2 +

2C H (d)CH 2

13. Which of the following groups can either donate or withdraw a pair of electrons in resonancedepending upon situation?(a) NO 2 (b) NO (c) CH = CH 2 (d) CHO

14. Functional group present in Oxirane(a) halide (b) carbonyl (c) alcohol (d) ether

15. Mesitylene having 3 Me group are at(a) 1, 2, 3 (b) 1, 2, 4 (c) 1, 3, 5 (d) 1, 2, 5

16. Tosyl chloride having following atoms(a) C, N, S, Cl (b) N,C, O, Cl (c) S, C, O, Cl (d) C, N, S, Cl

17. CH 3O CH = CH NO 2 ICH 2 = CH NO 2 IICH 2 = CH Cl IIICH 2 = CH 2 IVWhich of the following is the correct order of C-C bond lengths among these compounds.(a) I > II > III > IV (b) IV > III > II > I (c) I > III > II > IV (d) II > III > I > IV


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18. C 1 C2 bond is shortest in

(a)C CH

21 (b)

CH = CH 2 2

1 (c)CH 2 CH 3

21 (d)

C CH2

1

19. Which of the following has longest C O bond

(a) O (b) O (c) O (d) O

CH 2

20. Which is the correct order +I effect of the following groups/atoms(a) tbutyl > isopropyl > ethyl > methyl (b) D > H(c) O

> CO 2 (d) All21. Which is the correct order of I effect of the following groups/atoms ?

(a) F > Cl > Br > I (b) 3HN > NO 2 > CN > CO 2H(c) CO 2 R > SH > OH > C CR > CH = CR 2 (d) All

22. Which of the following statement is correct :(a) Inductive effect is distance independent (b) Inductive effective is temporary effect(c) Inductive effect occurs in saturated system (d) If effect stability of the molecule

which involves electrons

23. HO 2C CH CH OH the direction of electron movement would be(a) towards OH group (b) towards CO 2H group(c) at low temp towards OH group & at high temp towards CO 2H group(d) neither OH nor towards CO 2H group.

24. Heat of hydrogenation of cyclohexene to cyclohexane is 28.6 Kcals/mole. The observed heat of hydrogenation of benzene to cydohexane is 49.8 Kcals/mole. The resonance energy of benzene is(a) 48 Kcals/mole (b) 36 Kcals/mole (c) 24 Kcals/mole (d) 12 Kcals/mole

25. Which of the following represents resonating structure ?(a) H3C C CH 3

O

CH 3 C CH 3

OH &

(b) CH 3CN vs CH 3NC

(c) CH 3 C O vs H 3C +

C O

(d) H 2C CH OH & 2HC CH O H

26. Consider the following three halides:(I) CH 3 CH 2 Cl (II) CH 2 = CH Cl (III) C 6H5ClArrange C Cl bond length of these compounds in decreasing order :(a) I > II > III (b) I > III > II (c) III > II > I (d) II > III > I

27 Consider the given compounds(I) CH 3 CH 2 NH 2 (II) CH 3 CH = NH(III) CH 3 C N (IV) C 2H5 NH C2H5Arrange basicity of these compounds in decreasing order:(a) IV > I > II > III (b) I > II > III > IV (c) I > IV > II > III (d) IV > I > III > II


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28. Acyl cation has two resonating structures (I) and (II):

R C O R C O

(I) (II) Which statements is correct for (I) and (II) :(a) (I) is more stable than (II)(b) (II) is more stable than (I)(c) Stability of (I) and (II) will be the same

(d) For some time (I) will be more stable and for remaining time (II) will be more stable.

29. In pyridine;N

Number of conjugated electrons are:

(a) 6 (b) 8 (c) zero (d) 5

30.

HCH 3

HCH 3

H

H 3 C

CH 3H

H CH 3

H

H 3 C

I II are

(a) Conformational isomers (b) Stereoisomers(c) Constitutional isomers (d) Identical

31.

H

HCH 2

H

H

Y = Compound Y is projection formula of :

(a) Cyclohexane (b) Cyclopentane(c) Cyclobutane (d) Cyclopropane

32. Which is most stable conformation?

(a)

HMe

MeMe Me

H

(b)

MeMe

HMe Me

H

(c)

Me

MeMe

HH

Me

(d)

Me

HMe

HMe

Me

33. Select the correct statement/s:(a) Eclipsed and staggered ethanes give different products on reaction with chlorine in presence of

light.(b) The conformational isomers can be isolated at room temperature.(c) Torsional strain in ethane is minimum at dihedral angles 60 , 180 and 300 .(d) Steric strain is minimum in staggered gauche form of n-butane.

34 Which of the following statements regarding the projections shown below is true.

HCH 3

ClH H3C

Cl

a b

ClCH 3

CH 3H

ClH

(a) a and b both represent the same configuration (b) Both a and b are optically active (c) b alone is optically active (d) a alone is optically active


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35. O and

OHHOHH

HHOOHH

HCH 2OH

O are :

HHOOHH

HHOOHH

HCH 2OH

(a) Diastereomers (b) Enantiomers (c) Tautomers (d) Conformers

36. Which of the following is an achiral molecule?

(a)

HCl

ClCH 3 H3C

H

(b)

CH 3Cl

HCH 3 Br

H

(c)

CH 3H

OHCH 3 H

H 3 C

(d)

COOH OH

OHCOOH

H

H

37.. Which of the following compounds will show geometrical isomerism :(a) 2-butene (b) propene(c) 1-phenylpropene (d) 2-methyl-2-butene

38. The following can exhibit

CH 3

CH 3 C = C

Cl

C H

COOHCH 3

(a) Geometrical isomerism (b) geometrical and optical isomerisms(c) optically isomerism (d) tautomerism

39. Geometrical isomerism is shown by(a) H

HC = C

I

Br

(b) HH3C

C = CI

Br

(c) H3CH3C

C = CCl

Br

(d) HH3C

C = CCl

Cl

40 Meso tartaric acid is optically inactive due to the presence of :(a) Molecular symmetry (b) Molecular asymmetry(c) External compensation (d) Two asymmetric carbon atoms

41. The number of isomer for the compound with molecular formula C 2BrCl I F(a) 3 (b) 4 (c) 5 (d) 6

42. Magnitude of specific rotations of a compound is independent on(a) Temperature (b) Concentrations(c) length of polarimeter (d) Solvent

43. Enantiomers differ in(a) melting point (b) boiling point(c) solubility (d) Direction of optical rotation

44. Which of the following option is correct ?(a) In a pair of enantiomer one is d another is l.(b) Molecule with superimposable mirror image is optically inactive(c) all optically inactive compound is mesomer.(d) mesomer is possible only if compound has two or more similar asymmetric centre.

45. Which of the following option is correct ?(a) In a mesomer configuration of similar asymmetric centre will be opposite.(b) a mesomer is optically inactive because one half is d and other half is l.


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(c) An equimolar mixture of enantiomers is called racemic mixture.(d) Mirror image of an optical active isomer will have opposite configurations on all respective

asymmetric centre.

46.. Which of the following is (are) most likely to be D sugar ?

(a)

CHO

CH 2OH

HO HHO H (b)

CHO

CH 2 OH

HO H

H OH (c)

CHO

CH 2OH

H OHH OH (d)

CHO

CH 2OH

H OHHO H

47. An enantiomerically pure acid is treated with racemic mixture of an alchol having one chiral carbon.The ester formed will be :(a) Optically active mixture (b) Pure enantiomer(c) Meso compound (d) Reacemic mixture

48. Hydrogenation of the adjoining compoundin the presence of poisoned palladiumcatalyst gives :(a) an optically active compound(b) an optically inactive compound(c) a racemic mixture(d) a diastereomeric mixture.

Me H

Me H

Me

H

49 The optically active tartaric acid is named as D (+) tartaric acid because:(a) optical rotation and is derived from D glucose(b) pH in organic solvent(c) optical rotation an is derived from D (+) glyceraldehydes(d) optical rotation only when substituted by deuterium

50.. The no.of possible enantiomeric pair that can be produced during monochlorination of 2 methyl-butane is(a) 2 (b) 3 (c) 4 (d) 1

set of 50 obj in general organic chemistry by s.k.sinha

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