19 General Organic Chemistry Quiz | Chemistry Quiz #mcq.cetjob - Multiple choice questions and Objectives
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General Organic Chemistry Quiz | Chemistry Quiz

Carbon is an essential element of organic compounds, it has four electrons in its outer most shell.
According to the ground state electronic configuration of carbon, it is divalent. Tetravalency of carbon can be explained by promoting one of the 2S- electrons to the unoccupied 2P atomic orbital. 
The four valencies of the carbon atom are similar and they are symmetrically arranged around the carbon atom. According to Le Bell and Van’t Hoff the four valencies of carbon do not lie in one plane. They are directed towards the corners of a regular tetrahedron with a carbon atom at the center and the angle between any two valencies is 109o28.
Hybridization in Organic Compounds 
(1) The process of mixing atomic orbitals to form a set of new equivalent orbitals is termed as hybridization. There are three types of hybridization, 
(i) SP3 hybridization (involved in saturated organic compounds containing only single covalent bonds), 
(ii) SP2 hybridization (involved in organic compounds having carbon atoms linked by double bonds) and 
(iii) SP hybridization (involved in organic compounds having carbon atoms linked by triple bonds).

Bonding and hybridization in organic compounds Quiz

1. The number of sp2 hybridized carbon atoms in cyclohexene are
(a) 2 (b) 3
(c) 4 (d) 6

SOL: (c)

2. The number of pi bonds in 3-hexyne-1-ene is

(a) 1 (b) 2
(c) 3 (d) 4
SOL: (c)  

3. The compound in which carbon uses only its sp3 hybrid orbitals for bond formation is
(b) (NH2)2CO
(c) (CH3)3COH
(d) (CH3)3CHO 

SOL:  (c) All the carbon atoms are sp3 hybridized. 

4. The shape of ethylene molecule is
(a) Square planar (b) Furan 
(c) Trigonal planar (d) Tetrahedral
SOL:  (c) In ethylene molecule carbons are sp2 hybridised so its structure is trigonal planar

5. How many methyl group are present in 2, 5-dimethyl-4-ethylheptane
(a) 2 (b) 3
(c) 4 (d) 5
SOL:  (d) 

6. Allyl cyanide contain Sigma- and pi-bonds
(a) 9Sigma, 3pi (b) 9Sigma, 9pi
(c) 3Sigma, 4pi (d) 5Sigma, 7pi
SOL:  (a)

Dipole moment, resonance and reaction intermediates Quiz

7. Which of the following is observed in ethylene molecule

(a) Electromeric effect
(b) Inductive effect
(c) Homolytic fission
(d) None of these 
SOL:   A

8. Cyclopentadienyl anion is
(a) Aromatic
(b) Non-aromatic 
(c) Non-planar
(d) Aliphatic
SOL:   A

9. Orbital interaction between the sigma bonds of a substitutent group and a neighbouring pi orbital is known as
 (a) Hyperconjugation
(b) Inductive effect
(c) Steric effect
(d) Dipole-dipole interactions
(e) Electric quadruple interactions
SOL:   (a) It is hyperconjugation process. 

10. Which compound shows dipole moment
(a) 1,4-di-chloro benzene
(b) 1, 2-di-chloro benzene
(c) Trans-1, 2-di-chloro ethene
(d) Trans-2-butene 
SOL:   B

11. The dipole moment is the highest for
(a) Trans-2-butene
(b) 1, 3-Dimethylbenzene
(c) Acetophenone
(d) Ethanol
SOL:   C

12. Resonance structure of molecule does not have
(a) Identical arrangement of atoms
(b) Nearly the same energy content
(c) The same number of paired electrons
(d) Identical bonding
SOL:   (d) Resonance structure of molecule does not have identical bonding.

13. All bonds in benzene are equal due to
(a) Tautomerism
(b) Inductive effect
(c) Resonance
(d) Isomerism 
SOL:   C

14. Aromatic properties of benzene are proved by

(a) Aromatic sextet theory
(b) Resonance theory
(c) Molecular orbital theory
(d) All of these
SOL:    D

15. Which of the following free radicals is most stable

(a) Primary (b) Methyl
(c) Secondary (d) Tertiary

SOL:(d) Greater the no. of alkyl groups attached to the carbon atom carrying the odd electrons, greater is the delocalization of odd electron and hence more stable is the free radical. 

16. Which of the following contains three pairs of electrons

(a) Carbocation
(b) Carbanion
(c) Free radical
(d) None of these
SOL:    A
17. An aromatic compounds among other things should have a pi-electron cloud containing electrons where n can't be
(a) 1/2 (b) 3
(c) 2 (d) 1
SOL:    (a) According to Huckel ruel, all aromatic compounds must have (4n+2)pi electrons where   is an integer, i.e., n=1,2,3.. and possesses unusual stability due to the complete delocalisation of pi-electrons.

Organic reactions and their mechanism Quiz

18. Dehydrohalogenation of an alkyl halide is a/an
 (a) Nucleophilic substitution reaction
(b) Elimination reaction
(c) Both nucleophilic substitution and elimination reaction
(d) Rearrangement

SOL:    (b)Dehydrohalogenation of an alkyl halide on presence of alcoholic potash is an example of elimination reaction.


19. Addition of HCl to vinyl chloride gives 1, 1-dichloroethane because of
(a) Mesomeric effect of Cl
(b) Inductive effect of Cl
(c) Restricted rotation around double bond
(d) None of these
SOL:  (d)
It is addition reaction.
Which is according to Markownikoff rule. 

20. Formation of ethylene from acetylene is an example of
(a) Elimination reaction (b) Substitution reaction
(c) Addition reaction (d) Condensation reaction
SOL:    (c) 
That is called addition reaction.

21. Conversion of CH4 to CH3Cl is an example of which of the following reaction
(a) Electrophilic substitution
(b) Free radical addition
(c) Nucleophilic substitution
(d) Free radical substituion
SOL:    (d) When methane gas is treated with chlorine in the presence of sunlight, one hydrogen of methane  replaced by the chlorine atom and forms methyl chloride. The mechanism involved in this reaction is free radical mechanism. So it is an example of free radical substitution reaction

22. Geometry of reaction intermediate in SN1 reaction is
 (a) Tetrahedral (b) Planar
(c) Triangular bipyramidal (d) None of these

SOL:    B

23. In electrophilic substitution reaction nitrobenzene is 
 (a) Meta-directing
(b) Ortho-directing
(c) Para-directing
(d) Not reactive and does not undergo any substitution 
(e) Non-selective
SOL:    C

24. The most common type of reaction in aromatic compounds is
(a) Elimination reaction 
(b) Addition reaction
(c) Electrophilic substitution reaction
(d) Rearrangement reaction 
SOL:    C
25. The following compound will undergo electrophilic substitution more readily than benzene
(a) Nitrobenzene
(b) Benzoic acid
(c) Benzaldehyde
(d) Phenol
SOL:    D

26. Bromination of alkanes involves 
(a) Carbanions
(b) Carbocations
(c) Carbenes
(d) Free radicals
SOL:     (d) Halogenation of alkanes takes place in presence of light (sunlight or UV) or at elevated temperature via free radical.

27. Which of the following cannot undergo nucleophilic substitution under ordinary conditions
(a) Chlorobenzene
(b) tert-butylchloride
(c) Isopropyl chloride
(d) None of these
SOL:    (d) All the given species undergo nucleophilic substitution reaction. This reactivity can be explained in terms of the nature of C-X bond which is highly polarised covalent bond due to large difference in the electronegativities of carbon and halogen atoms.

28. Addition of HCl to vinyl chloride gives 1, 1-dichloroethane because of
(a) Mesomeric effect of Cl
(b) Inductive effect of Cl
(c) Restricted rotation around double bond
(d) None of these
SOL:   D 

29. Formation of ethylene from acetylene is an example of
(a) Elimination reaction (b) Substitution reaction
(c) Addition reaction (d) Condensation reaction
SOL:    (c) 

Structural and stereoisomerism Quiz

30. Lactic acid shows which type of isomerism
(a) Geometrical isomerism
(b) Tautomerism
(c) Optical isomerism
(d) Metamerism
SOL:    C

31. Which one of the following is an optically active compound
(a) n-propanol
(b) 2-chlorobutane
(c) n-butanol
(d) 4-hydroxyheptane 
SOL:    (b) because they contain chiral carbon atom.

32. Compounds with same molecular formula but different structural formulae are called
(a) Isomers (b) Isotopes
(c) Isobars (d) Isoelectronic
SOL:    A

33. Rotation of plane polarised light is measured by
(a) Manometer
(b) Polarimeter
(c) Viscometer
(d) Refractometer 
SOL:    B

34. An alkane forms isomers if the number of least carbon atom is
(a) 1 (b) 2
(c) 3 (d) 4


35. Which is not found in alkenes
(a) Chain isomerism
(b) Geometrical isomerism
(c) Metamerism
(d) Position isomerism
SOL:    (c)  Metamerism is a special types of isomerism shown by secondary amines, ethers and ketones.
36. The compound C4H10O can show

(a) Metamerism
(b) Functional isomerism
(c) Positional isomerism
(d) All types 
SOL:    (d) Optically active isomers but not mirror images are called
37. C7H9N has how many isomeric forms that contain a benzene ring
(a) 4 (b) 5
(c) 6 (d)
SOL:    B

38. The total number of isomers formed by C5H10  is
(a) 2 (b) 3
(c) 4 (d) 5
(e) None of these
SOL:    D

39. Which of the following contains asymmetric centre
(a) 2-butene
(b) 2, 2-dimethylpropane
(c) 2-hexyne
(d) Lactic acid 
SOL:    D

40. Which of the following cannot be given to exemplify chiral structure
(a) A shoe (b) A screw
(c) A screw driver (d) All of these
SOL:    D

41. The maximum number of stereoisomers possible for 2-hydroxy-2-methyl butanoic acid is
(a) 1 (b) 2
(c) 3 (d)
SOL:    (b) 

42. Which one of the following pairs represents the stereoisomerism
(a) Geometrical isomerism, position isomerism
(b) Geometrical isomerism, conformational isomerism
(c) Optical isomerism, geometrical isomerism
(d) Optical isomerism, metamerism
SOL:    (c)  Optical isomerism and geometrical isomerism.

43. Number of isomers of C4H10 is
(a) 2
(b) 3
(c) 4
(d) Isomerism not exist 
SOL:     (a)   ,   

44. Diethyl ether and methyl n-propyl ether are
(a) Position isomers
(b) Functional isomers
(c) Metamers
(d) Chain isomers

SOL:    (c)  

45. It is possible to distinguish between optical isomers by
(a) Infrared spectroscopy
(b) Mass spectrometry
(c) Melting point determination
(d) Polarimetry
SOL:    D

46. The isomerism exhibited by alkyl cyanide and alkyl isocyanide is
(a) Functional (b) Positional
(c) Tautomerism (d) Metamerism
SOL:    (a)  

47. Geometrical isomerism is not possible in
(a) Propene
(b) 3-hexane
(c) Butenedioic acid
(d) Cyclic compound 
SOL:    (a)  Geometrical isomerism is not possible in propene.

48. Only two isomeric monochloro derivatives are possible for
 (a) 2-methyl propane
(b) n-pentane 
(c) Benzene
(d) 2, 4-dimethyl pentane
SOL:   (a) Two isomeric forms are possible for 2-methyl propane.

49. Lactic acid in which a methyl group, a hydroxyl group, a carboxylic acid group and a hydrogen atom are attached to a central carbon atom, shown optical isomerism due to the molecular geometry at the 
(a) Central carbon atom
(b) Carbon atom of the methyl group
(c) Carbon atom of the carboxylic acid group
(d) Oxygen of the hydroxyl groups
SOL:    A

50. The number of possible alkynes with molecular formula  C5H8  is 
(a) 2 (b) 3
(c) 4 (d) 5
SOL:    B

51. Which compound is chiral
(a) butane
(b) 1-chloro-2-methyl butane
(c) 2-methyl butane
(d) 2-methyl propane 


52. Methyl acetate and propionic acid are
(a) Functional isomer
(b) Structural isomer 
(c) Stereoisomer
(d) Geometrical isomer
SOL:    (a) Functional isomerism

53. Which compound shows cis-trans isomerism
(a) 1-butene (b) 2-propene
(c) 2-butene (d) Benzene 
SOL:    C

54. Glucose has optical isomers
(a) 8
(b) 12
(c) 16
(d) Cannot be predicted
SOL:    C

55. Which of the following statements is not true about enantiomers
(a) They have same physical properties
(b) They have different biological properties
(c) They have same chemical properties towards chiral compounds 
(d) None of these
SOL:    (a) Enantiomers have same chemical properties but different physical properties.

56. Meso-tartaric acid is
(a) Optically inactive
(b) Optically active because of molecular symmetry
(c) Optically inactive due to external compensation
(d) Optically active because of asymmetric carbon atom 
SOL:    A

57. The number of possible isomers of the compound with molecular formula  C7H8O  is
(a) 3 (b) 5
(c) 7 (d) 9
SOL:    D

58. Ethyl acetoacetate shows, which type of isomerism
 (a) Chain
(b) Optical
(c) Metamerism
(d) Tautomerism 
SOL:    (d) 
59. Which of the following will have a mesoisomer also
 (a) 2, 3-Dichloropentane
(b) 2, 3-Dichlorobutane
(c) 2-Chlorobutane
(d) 2-Hydroxypropanoic acid
SOL:    (b)  

60. A compound has 3 chiral carbon atoms. The number of possible optical isomers it can have
(a) 3 (b) 2
(c) 8 (d) 4
SOL:    (c) 

61. How many chiral isomers can be drawn from 2-bromo, 3-chloro butane
(a) 2 (b) 3
(c) 4 (d) 5
SOL:    (c) 2-bromo, 3-chloro-butane has 2 chiral carbon atoms, hence has 4 optical isomers.