20 Hydrocarbons Quiz | Chemistry Quiz #mcq.cetjob - Multiple choice questions and Objectives
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Hydrocarbons Quiz | Chemistry Quiz

Aliphatic Hydrocarbon
Organic compounds composed of only carbon and hydrogen are called hydrocarbons. Hydrocarbons are two types 
(1) Aliphatic Hydrocarbon (Alkanes, Alkenes, and Alkynes). 
(2) Aromatic Hydrocarbon (Arenes) 
(1) Sources of aliphatic hydrocarbon 
Mineral oil or crude oil, petroleum [Petra  rock; oleum  oil] is the dark color oily liquid with offensive odor found at various depths in many regions below the surface of the earth. It is generally found under the rocks of the earth’s crust and often floats over salted water.
(2) Composition
(i) Alkanes: found 30 to 70% contain up to 40 carbon atom. Alkanes are mostly straight-chain but some are branched-chain isomers.
(ii) Cycloalkanes : Found 16 to 64% cycloalkanes present in petroleum are; cyclohexane, methyl cyclopentane etc. cycloalkanes rich oil is called asphaltic oil.
(iii) Aromatic hydrocarbon : found 8 to 15% compound present in petroleum are; Benzene, Toluene, Xylene, Naphthalene etc.

Alkane Quiz

1. Petroleum consists mainly of
(a) Aliphatic hydrocarbons
(b) Aromatic hydrocarbons
(c) Aliphatic alcohols
(d) None of these

Sol: A

2. Petroleum ether can be used as
(a) Solvent for fat, oil, varnish and rubber
(b) As a fuel
(c) Both (a) and (b)
(d) None of these

Sol:  (a) Solvent for fat, oil, varnish and rubber 

3. Which of the following are produced from coaltar
(a) Synthetic dyes
(b) Drugs
(c) Perfumes
(d) All the three

Sol:  (d) Synthetic dyes, drugs, perfumes all are made from coal tar.

4. In alkanes, the bond angle is
(a) 109.5 (b) 109
(c) 120 (d) 180

Sol:  (a) In alkanes, hybridization is sp3. Hence bond angle is 109.5.

5. In the preparation of alkanes; a concentrated aqueous solution of sodium or potassium salts of saturated carboxylic acid are subjected to
(a) Hydrolysis (b) Oxidation
(c) Hydrogenation (d) Electrolysis

Sol:   (d)

6. Halogenation of alkanes is an example of
(a) Electrophilic substitution
(b) Nucleophilic substitution
(c) Free-radical substitution
(d) Oxidation
Sol:  c

7. Petroleum is mainly a mixture of
(a) Alkanes
(b) Cyclohexane 
(c) Benzenoid hydrocarbons
(d) Alkenes
Sol:   A

8. Which of the following has maximum boiling point 

(a) iso-octane
(b) n-octane
(c) 2, 2, 3, 3-tetramethyl butane
(d) n-butane
Sol:  (b) n–octane
 •  Boiling point depends on molecular mass.  Greater the molecular mass higher will be the boiling point.
Boiling point also depends on the structure. If two compounds have same molecular mass then straight chain or linear compound has higher boiling point.

9. Aqueous solution of the following compound on electrolysis gives ethane
(a) Acetic acid
(b) Acetamide
(c) Potassium acetate
(d) Ethyl acetate

Sol:  (c)

10. Which of the following does not decolourise bromine solution in carbon disulphide
(a) Acetylene (b) Propene
(c) Ethane (d) Propyne

Sol:  (c) Ethane does not decolourise bromine solution because it is a saturated compound. 

11. Anhydrous sodium acetate on heating with sodalime gives
(a) Acetic acid (b) Methane
(c) Calcium acetate (d) Ethane

Sol:  (b)

12. A sample of gasoline contains 81% iso-octane and 19% n-heptane. Its octane number will be
(a) 19 (b) 81
(c) 100 (d) 62

Sol:  (b) Octane number is related to the percentage of iso-octane since iso-octane is 81% hence octane number is 81%.

13. The natural petroleum contains
(a) Saturated hydrocarbons
(b) Cyclic saturated hydrocarbons
(c) Compounds of sulphur
(d) All of these

Sol:  D

14. Which of the following statements is incorrect ? The members of the homologous series of alkanes
(a) Are all straight chain compounds
(b) Have the general formula CnH2n+2
(c) Have similar chemical properties
(d) Show a regular gradation of physical properties
Sol:   A

15. On mixing tetraethyl lead to gasoline available at petrol pumps
(a) Calorific value of the fuel increases
(b) Odour diminishes
(c) Less smoke is obtained on combustion
(d) Antiknock property of fuel increases
Sol:  (d) Anti-knocking properties of fuel increases. 

16. A liquid hydrocarbon can be converted to gaseous hydrocarbon by
(a) Cracking
(b) Hydrolysis
(c) Oxidation
(d) Distillation under reduced pressure
Sol:  (a)

17. The tetrahedral nature of carbon was first given by
(a) Kekule
(b) Le Bell and Van't Hoff
(c) Pauling
(d) Armstrong and Bayer
Sol:  B

18. Formation of alkane by the action of Zn on alkyl halide is called
(a) Frankland's reaction
(b) Wurtz reaction
(c) Cannizzaro reaction
(d) Kolbe's reaction

Sol:  A

19. Which of the following has the highest boiling point
(a) Neopentane (b) n-butane
(c) n-heptane (d) Isobutane
Sol:  C

20. Which gives CH4 when treated with water
(a) Silicon carbide
(b) Calcium carbide
(c) Aluminium carbide
(d) Iron carbide
Sol:  (c)

21. A reaction between methyl magnesium bromide and ethyl alcohol gives
(a) Methane
(b) Ethane
(c) Propane
(d) Butane
Sol:   A

22. A liquid hydrocarbon can be converted to gaseous hydrocarbon by
(a) Cracking
(b) Hydrolysis
(c) Oxidation
(d) Distillation under reduced pressure
Sol:    (a)  
23. The tetrahedral nature of carbon was first given by
(a) Kekule
(b) Le Bell and Van't Hoff
(c) Pauling
(d) Armstrong and Bayer
Sol:    B

24. Formation of alkane by the action of Zn on alkyl halide is called
(a) Frankland's reaction
(b) Wurtz reaction
(c) Cannizzaro reaction
(d) Kolbe's reaction
Sol:   A

25. Name the hydrocarbon that is a liquid at STP
(a) Ethane (b) Propane
(c) n-butane (d) n-pentane
Sol:   D

26. A mixture of ethyl iodide and n-propyl iodide is subjected to Wurtz reaction. The hydrocarbon that will not be formed is
(a) n-butane (b) n-propane
(c) n-pentane (d) n-hexane
Sol:   C

27. Most of the hydrocarbons from petroleum are obtained by 
(a) Fractional distillation
(b) Fractional crystallization
(c) Vaporization
(d) Polymerization
Sol:    Fractional distillation is based on the difference in the boiling point of different components.

28. Which is the best antiknock compound or Which one of the following substances is used as an antiknock compound
(a) Lead tetrachloride
(b) Lead acetate
(c) Zinc ethyl
(d) Tetraethyl lead (TEL)
Sol:   (d) Tetraethyl lead (TEL) is an anti-knocking compounds when mixed with petrol tend to improve the octane no. and therefore, decreases the knocking in the cylinder of the combustion engine. 

29. In the dichlorination reaction of propane, mixture of products are obtained. How many isomers, the mixture contains
(a) 2 (b) 3
(c) 4 (d) 5
Sol:   C

30. Methane can be prepared by
(a) Wurtz's reaction
(b) Decarboxylation
(c) Hydrogenation reaction
(d) All of these
Sol:    (b)

31. The most strained cycloalkane is
(a) Cyclopropane (b) Cyclobutane
(c) Cyclopentane (d) Cyclohexane
Sol:    A

32. Which of the following method can be used for the preparation of methane
(a) Wurtz reaction
(b) Kolbe's reaction
(c) Reduction of alkyl halide
(d) Hydrogenation of alkene
Sol:   (c)  

33. Which  hydrocarbon will be most stable
 (a) Methane (b) Ethane
(c) Propane (d) Butane

Sol:   D

Alkene Quiz

34. Which of the following compounds represents acrylonitrile
(a) Vinyl cyanide
(b) Cyanoethene
(c) Prop-2-ene nitrile
(d) All of them
Sol:    D

35. When acetylene reacts with arsenic trichloride in the presence of anhydrous aluminium chloride, it produces 
 (a) Lewisite
(b) Beeta-chlorovinyl dichloroarisine
(c) Nitrobenzene
(d) Both (a) and (b)
Sol:   D

36. Ozonolysis of which one of the following will give two molecules of acetaldehyde
(a) 1-butene (b) 2-butene
(c) 1-pentene (d) 2-pentene
(e) None of these
Sol:   B

37. In which of the following, addition of   does not take place against Markownikoff's rule or Anti-Markownikoff addition of   is not observed for
(a) Propene (b) But-1-ene
(c) But-2-ene (d) Pent-2-ene

Sol:  (c) Anti-markownikoff’s rule is not applicable to symmetrical alkenes.

38. Which one of the following characteristics apply to both ethene and ethyne
(a) Explode when mixed with chlorine
(b) Decolourise Baeyer's reagent giving brown precipitate
(c) Rapidly absorbed by cold conc. H2SO4
(d) Form white precipitate with silver nitrate solution
Sol: (b)
39. During debromination of meso-dibromobutane, the major compound formed is
(a) n-butane
(b) 1-butane
(c) cis-2-butene
(d) trans-2-butene
Sol:   D

40. What product is formed when 1-chlorobutane react with alcoholic KOH
(a) 1-butene (b) 2-butene
(c) 1-butanol (d) 2-butanol
Sol:    (a)

41. Bond length between carbon-carbon in ethylene molecule is

(a) 1.54 Å (b) 1.35 Å
(c) 1.19 Å (d) 2.4 Å
Sol:   B

42. The compound having both sp and   hybridised carbon atom is
(a) Propene
(b) Propyne
(c) Propadiene
(d) None of these
Sol:   (c)  
Propadiene has both sp and sp2-hybridized carbon atoms.

43. The halogen which is most reactive in the halogenation of alkenes under sunlight is 
(a) Chlorine (b) Bromine
(c) Iodine (d) All equal
Sol:   (a)

44. One mole of each of the following alkenes is catalytically hydrogenated. The quantity of heat evolved will be the lowest in the case of
(a) 1-butene
(b) Trans-2-butene
(c) Cis-2-butene
(d) 1, 3-butadiene
Sol:   D

45. Electrophilic addition on a carbon-carbon double bond involves the intermediate formation of a more stable carbocation. This statement is called
(a) Saytzeff's rule
(b) Baeyer's effect
(c) Markownikoff's rule
(d) None of these
Sol:   C

46. Presence of peroxides affects the addition of
(a) HBr (b) HCl
(c) HI (d) All of these
Sol:   (a) Peroxide rule is applicable only to HBr and not for HCl, HF and HI. 

47. Chloroprene is
(a) 2-chloro-1, 3-butadiene
(b) 3-chloro-2, 3-butadiene
(c) 2, 3-dichlorobutadiene
(d) None of these
Sol:   A

48. Electrolysis of cold concentrated aqueous solution of potassium succinate yields
(a) Ethane
(b) Ethyne
(c) Ethene
(d) Ethane-1, 2-diol
Sol:    (c)  

49. A hydrocarbon containing 2 carbon atoms gives Sabatier and Senderen's reaction but does not give precipitate with ammoniacal silver nitrate solution. The hydrocarbon in the question is
(a) Ethane
(b) Acetylene
(c) Ethylene
(d) None of these
Sol:   (c)
Ethylene does not give precipitate with ammonical silver nitrate solution because it does not have acidic hydrogen.

50. “The negative part of addenda adds on to the carbon atom linked with least number of hydrogen atoms”. This statement is called
(a) Thiele's principle
(b) Bayer's strain theory
(c) Markownikoff's rule
(d) Peroxide effect
Sol:    (c)  

51. Which of the following is the most stable
(a) 1-butene (b) 2-butene
(c) 1-pentene (d) 2-pentene

Sol:    (d) will be the most stable because greater the number of alkyl groups attached to double bonded carbon atoms, more stable is the alkene.

Alkyne Quiz

52. By coaltar distillation, which is not obtained
(a) Light oil (b) Middle oil
(c) Heavy oil (d) Mobil oil
Sol:    D

53. The shapes of methane, ethene and ethyne molecules are, respectively
(a) Tetrahedral, planar and linear
(b) Tetrahedral, linear and planar
(c) Pyramidal, planar and linear
(d) Tetrahedral, pyramidal and planar
Sol:    A

54. Propyne on polymerisation gives
(a) Mesitylene (b) Benzene
(c) Ethyl benzene (d) Propyl benzene
Sol:    A

55. Benzene is the polymer of
(a) Methane (b) Ethane
(c) Ethylene (d) Ethyne

Sol:    B

56. Acetylene is prepared industrially by passing electric discharge through graphite electrodes in the atmosphere of 
(a) Air (b) N2
(c) H2 (d) CO2
Sol:    (c)

57. When acetylene is passed into dilute sulphuric acid containing Hg2+  ions, the product formed is

(a) Acetone
(b) Acetic acid
(c) Acetaldehyde
(d) Formaldehyde
Sol:    (c)

58. The number of pi-bonds in the product formed by passing acetylene through dilute sulphuric acid containing mercuric sulphate is
(a) Zero (b) One
(c) Two (d) Three
Sol:    (b) 

59. Which of the following reactions is shown by alkynes
(a) Addition (b) Substitution 
(c) Polymerization (d) All of these
Sol:    (d) Addition –   

Aromatic hydrocarbon Quiz

60. On heating a mixture of sodium benzoate and sodalime, the following is obtained

(a) Toluene
(b) Phenol
(c) Benzene
(d) Benzoic acid
Sol:    C

61. What is the end product which is obtained on the nitration of toluene
(a) o-nitrotoluene
(b) p-nitrotoluene
(c) 2, 4-dinitrotoluene
(d) 2, 4, 6-trinitrotoluene
Sol:    D

62. Which of the following processes is reversible
(a) Halogenation
(b) Sulphonation
(c) Nitration
(d) None
Sol:    B

63. Which xylene is most easily sulphonated
(a) Ortho
(b) Para
(c) Meta
(d) All at the same rate
Sol:    C

64. Aromatic compounds burn with sooty flame because

(a) They have a ring structure of carbon atoms
(b) They have a relatively high percentage of hydrogen
(c) They have a relatively high percentage of carbon
(d) They resist reaction with oxygen of air

Sol:    (c) They have a relatively high percentage of carbon 

65. Among the following compound which one is planar in shape
(a) Methane (b) Acetylene
(c) Benzene (d) Isobutane
Sol:    (c) All 6 carbons of Benzene are sp2 -hybridised so it is planar

66. Among the following statements on the nitration of aromatic compounds, the false one is
(a) The rate of nitration of benzene is almost the same as that of hexadeuterobenzene
(b) The rate of nitration of toluene is greater than that of benzene
(c) The rate of nitration of benzene is greater than that of hexadeuterobenzene
(d) Nitration is an electrophilic substitution reaction
Sol:    C

67. Catalytic hydrogenation of benzene gives
(a) Xylene
(b) Cyclohexane
(c) Benzoic acid
(d) Toluene
Sol:    B

68. Benzene is obtained from 
(a) Coaltar (b) Plant
(c) Animal (d) Charcoal
Sol:    C

69. In presence of light toluene on reaction with chlorine gives

(a) Benzoyl chloride
(b) Ortho chlorotoluene
(c) Para chloro toluene
(d) Benzyl chloride
Sol:    D

70. Benzene can be obtained by heating either benzoic acid with X or phenol with Y. X and Y are respectively  
 (a) Zinc dust and soda lime
(b) Soda lime and zinc dust
(c) Zinc dust and sodium hydroxide
(d) Soda lime and copper
Sol:   (b)

71. Which of the following yield both alkane and alkene 
 (a) Kolbe’s reaction
(b) Williamson’s synthesis
(c) Wurtz reaction
(d) Sandmeyer reaction

Sol:. (a) Kolbe’s methods – Electrolysis of a concentrated aqueous solution of either sodium or potassium salts of saturated mono carboxylic acids yields higher alkanes at anode.

72. Which kind of isomerism will butene-2 show
(a) Geometrical
(b) Optical
(c) Position
(d) None of these

Sol:    (a) 2-butene shows geometrical isomerism.