Hydrocarbons MCQs – 4

1) During chlorination of methane to methyl chloride, the propagation step is represented by
a)
b)
c)
d)

2) Methane reacts with excess of chlorine in diffused sunlight to give the final product
a) Chloroform
b) Carbon tetrachloride
c) Methylene chloride
d) Methyl chloride.

3) An alkane with molecular weight 72 upon chlorination gives only one monochlorination product. The alkane is
a) 2-Methylbutane
b) n-Pentane
c) 2, 2-Dimethylpropane
d) All the three above.

4) Which alkane of molecular weight 72 would give three and only three different monochloro derivatives ?
a) n-Pentane
b) Isopentane
c) n-Hexane
d) Isohexane.

5) The number of monochloro derivatives of isohexane is
a) 3
b) 4
c) 5
d) 6

6) CH3CH2CH2CH3 A (2-chlorobutane )+ B(1-chlorobutane ). The approximate ratio of percentage yields of A and B formed in the above reaction is
a) 50 : 50
b) 72 : 28
c) 45 : 55
d) 60 : 40.

7) Photochemical bromination of n-butane produces
a) 1 -Bromobutane as the major product
b) 2-Bromobutane as the major product
c) Both 1-bromobutane and 2-bromobutane with equal percentage
d) Both 1-bromobutane and 2-bromobutane whose percentages depend upon temperature.

8) The major monochloro product obtained when isobutane is treated with chlorine in the presence of diffuse light in
a) Isobutyl chloride
b) n-Butyl chloride .
c) tert-Butyl chloride
d) sec-Butyl chloride.

9) The major product obtained in the photobromination of 2- methylbutane is
a)
b)
c)
d)

10) lodination of an alkane is carried out in the presence of
a) Alcohol
b)
c)
d) A reducing agent

11) Isomerization of an alkane may be carried out by using
a) NaOH
b) HI/P
c) Anhydrous aluminium chloride
d) Con.HCl

12) Which of the following alkanes can be easily aromatized catalytically ?
a) n-Butane
b) Isobutane
c) n-Pentane
d) n-Hexane.

13) Which of the following decolourises a hot KMnO4 solution ?
a)
b)
c)
d)

14) Which of the following is not an oxidation product of an alkane ?
a) Alcohol
b) Aldehyde
c) Carboxylic acid
d) Ether.

15) Converting n-hexane into benzene in the presence of chromium oxide on alumina support is an example of a
a) Hydrogenation reaction
b) Isomerisation reaction
c) Aromatization reaction
d) Substitution reaction.

16) When n-heptane is heated to about 773 K under high pressure and in presence of Cr2O3 deposited over AI2O3, the final product formed is
a) Cyclohexane
b) Methylcyclohexane
c) Toluene
d) Benzene

17) Which one of the following is an electrophilic addition reaction?
a)
b)
c)
d)

18) The reaction of ethene with Br2 in CCI4 gives :
a) Bromoethane
b) 1,2-Dibromoethane
c) 1,1-Dibromoethane
d) 1,1,2,2, -Tetrabromoethane.

19) The addition of halogen to an alkene involves the intermediate formation of a
a) Carbocation
b) Carbanion
c) Free radical
d) Cyclic halonium ion.

20) Which of the following products is not formed when ethylene is bubbled through an aqueous solution of bromine containing sodium chloride?
a) 1,2-Dibromoethane
b) 2-Bromo-1-chloroethane
c) 2-Bromoethanol
d) 1,2 – dichlorocthane .

21) Cyclohexene reacts with Br2 in CCI4 to form
a) cis-1, 2-Dibromocyclohexane
b) trans-1,2-Dibromocyclohexane
c) Bromocyclohexane
d) None of the above.

22) The most stable alkene among the following is
a)
b)
c)
d)

23) rule governs the addition of
a) Unsymmetrical reagents to symmetrical alkenes
b) Symmetrical reagents to unsymmetrical alkenes
c) Unsymmetrical reagents to unsymmetrical alkenes
d) Symmetrical reagents to symmetrical alkenes.

24) Which of the following reacts most readily with conc. H2SO4 ?
a)
b)
c)
d) All the three above

25) Propylene is passed through cone. H2SO4 and the product thus obtained on hydrolysis with boiling water gives
a) 1-Propanol
b) 2-Propanol
c) 1-Propanal
d) 2-Propanal.

26) HBr adds to propene to form 1 -bromopropane according to
a) the peroxide effect
b)
c) Seytzeff rule
d) All of the above

27) Addition of CI2 water (or HOCI) to propene gives
a) 1 -Chloro-2-propanol
b) 2-Chloro-1-propanol
c) 3-Chloro-1-propanol
d) 1-Chloro-1-propanol.

28) The addition of HCI to 2-methyl-2-butene mainly gives
a) 1-Chloro-2-methylbutane
b) 2-Chloro-2-methylbutane
c) 2-Chlorobutane
d) 1-Chlorobutane.

29) The peroxide effect is observed
a) Only with HBr
b) Only with HI
c) Only with HCI
d) Only with HF.

30) The addition of HCI in presence of peroxide does not follow anti- rule because the
a) HCI bond is too strong to be broken homolytically
b) Cl atom is not reactive enough to add on to a double bond
c) Cl atom combines with H atom to form HCI
d) HCI is a reducing agent.

31) The addition of HI in the presence of peroxide does not follow anti- rule because
a) HI bond is too strong to be broken homolytically
b) I atom is not reactive enough to add on a double bond
c) I combines with H to give back HI
d) HI is a reducing agent.

32) In which of the following reactions, addition does not occur according to rule ?
a)
b)
c)
d)

33) An alkene with molecular formula C4H8 upon ozonolysis gives one mole of propanone and one mole of methanal. The alkene is
a) 1-Butene
b) 2-Methylpropene
c) 2-Butene
d) 2-Methyl-2-butene.

34) Which of the following alkenes will give O = CH-CH2-CH2-CH2-CH2-CH = O when treated with ozone and then with zinc and water ?
a) 1-Hexene
b) 2-Hexene
c) 3-Hexene
d) Cyclohexene.

35) CH2 = CH-CH=CH2
a)
b)
c)
d)

36) Which of the following reagents cannot be used to distinguish between propane and propene ?
a)
b)
c)
d)

37) Cyclohexane and 1-hexene have the same molecular formula. A simple chemical test that will distinguish one from the other is
a)
b)
c) Bromine water
d) TollenÂ’s reagent

38) Ethylene combines with sulphur monochloride to form
a) Phosgene
b) Mustard gas
c) Methyl isocyanate (MIC)
d) Lewisite.

39) An alkene on vigorous oxidation with KMnO4 gives only acetic acid. The alkene is
a)
b)
c)
d)

40) Oxidation of 1-butene with hot KMnO4 solution produces
a)
b)
c)
d)

41) Which of the following alkenes on oxidation with hot KMnO4 will give only CH3-CO-(CH2)4-CO-CH3 ?
a) Cyclohexene
b) 1-Methylcyclohexene
c) 1, 2-Dimethylcyclohexene
d) 1, 2-Dimethylcyclopentene.

42) An alkene with the molecular formula C8H16 on oxidation with hot KMnO4 gives acetone and 3-pentanone. The structure of the alkene is
a)
b)
c)
d)

43) An alkene with the molecular formula C6H12 on oxidation with hot KMnO4 solution gives only HOOC-(CH2)4-COOH. The alkene is
a) Cyclohexene
b) 1-Methylcyclopentene
c) 1,2-Dimethylcyclobutene
d) 3-n-Propylcyclopentene.

44) Which of the following can act as both an electrophile and a nucleophile ?
a) Alkanes
b) Cycloalkanes
c) Alkenes
d) Aldehydes and ketones.

45) Which of the following will react most readily with bromine ?
a)
b)
c)
d)

46) Acetylene can be converted to acetaldehyde by the
a) Action of HOCI
b)
c)
d) By passing through a red hot iron tube.

47) The product/s obtained when 1-pentyne is reacted with H2O, H+, Hg2+ is/are
a)
b)
c)
d)

48) The reagent required to convert 1-butyne to 2-butanone is/are
a)
b)
c)
d)

49) Which of the following reagents on interaction would form 2, 2- dibromopropane ?
a) HC = CH + 2 HBr
b)
c)
d)

50) When 1 -butyne is treated with excess of HBr, the expected product is
a) 1, 2-Dibromobutane
b) 2, 2-Dibromobutane
c) 1, 1-Dibromobutane
d) All the above.

51) 1-Butyne can be converted into 1-bromo-1-butene by reacting it with which of the following reagent ?
a) HBr
b)
c)
d)

52) A mixture of acetylene and HCN in the ratio of 2 : 1 was passed through a red hot tube. The product formed is
a) Benzene
b) Pyridine
c) Pyrrole
d) Thiophene.

53) When acetylene is passed through a solution of sodium hypochlorite at 273 K in absence of air and light, the product formed is
a) 1, 1, 2, 2-Tetrachloroethane
b) Sodium acetylide
c) 1,2-Dichloroethene
d) 1, 2-Dichloroethyne.

54) Which of the following compounds on treatment with methanol in presence of potassium methoxide under pressure at 433 K will give methyl vinyl ether ?
a) Ethyne
b) Ethene
c) Propyne
d) 1, 3-Butadiene.

55) Acrylonitrile is given by the reagents
a) Acrylic acid and KCN
b) Ethyne and KCN
c) Ethyne and HOCI
d)

56) In presence of nickel cyanide, acetylene gives
a) Benzene
b) Cyclooctatetraene
c) Cyclohexatriene
d) Cyclobutadiene.

57) Acetylene reacts with excess of hypochlorous acid to produce
a) Acetylene tetrachloride
b) Acetylene chlorohydrin
c) Acetaldehyde
d) Dichloroacetaldehyde.

58) Propyne when reacted with excess of HOCI gives
a) 1, 1, 2, 2-Tetrachloropropane
b) Propylene chlorohydrin
c) Acetone
d) 1, 1-Dichloropropanone.

59) When acetylene is passed through a solution of cuprous chloride and ammonium chloride in the presence of hydrochloric acid, it gives
a) Only vinylacetylene
b) Only divinylacetylene
c) Both vinylacetylene and di-vinylacetylene
d) None of these.

60) The gas which gives benzene on passing through a red hot iron tube is
a)
b)
c)
d)

61) Propyne when passed through a hot iron tube at 773 K produces
a) Benzene
b) Toluene
c) m-Xylene
d) Mesitylene.

62) The reaction,CH CH+NaNH2CH C Na+ +NH3 shows that the hydrogen atoms of acetylene are
a) Acidic
b) Basic
c) Neutral
d) Amphoteric.

63) Which of the following is the correct increasing order of acidity ?
a) Ethyne, ethane, ethene
b) Ethane, ethene, ethyne
c) Ethene, ethyne, ethane
d) Ethane, ethyne, ethene.

64) The order of relative acidic strength of water, ammonia and acetylene is
a) Water > ammonia > acetylene
b) Ammonia > water > acetylene
c) Water > acetylene > ammonia
d) Acetylene > water > ammonia.

65) From the following reactions,
HC CH+LiNH2 NH3+HC CLi
H2O + HC CLi HC CH+LiOH
predict which of the following orders about base strength is correct.

a)
b)
c)
d)

66) From the following reactions,
HCCH+LiNH2NH3+HC+CLi
NH3+RNH+RH
predict which of the following orders regarding acid strength is correct ?

a)
b)
c)
d)

67) The treatment of with RC s CH produces
a) RH
b)
c) R – R
d)

68) Which of the following reagents would you prefer to find out whether the hydrocarbon C3H4 contains one-triple bond or two-double bonds ?
a)
b)
c)
d)

69) A five carbon atom alkyne forms a sodium salt on treatment with sodamide. The alkyne is
a) only
b) only
c) only
d) Either (a) or (c).

70) A mixture of ethane, ethylene and acetylene gases is passed through a bottle containing ammoniacal silver nitrate solution. The gas coming out is
a) Ethane
b) Acetylene
c) Both ethane and ethylene
d) Original mixture.

71) A gas decolourises cold aqueous alkaline KMnO4 solution but does not give a precipitate with ammoniacal CuCI solution. The gas is
a) Methane
b) Ethane
c) Ethylene
d) Acetylene.

72) Which of the following characteristics apply to both ethene and ethyne ?
a) Explode when mixed with chlorine
b) Decolourise Baeyers reagent giving a brown precipitate
c)
d) Form white precipitate with silver nitrate solution.

73) A metallic carbide on treatment with water gives a colourless gas which burns with a luminous flame and gives a white precipitate with ammoniacal silver nitrate. The gas is
a) Methane
b) Ethane
c) Ethylene
d) Acetylene.

74) Which of the following reagents will qualitatively distinguish between 1-butyne and 2-butyne ?
a)
b)
c)
d)

75) Which of the following reacts with an aqueous solution of [Ag(NH3)2]+ OH?
a)
b)
c)
d)

76) Alkaline KMnO4 oxidation of acetylene gives
a) Oxalic acid
b) Acetic acid
c) Formic acid
d) Glyoxal.

77) Acetylene on oxidation with chromic acid gives
a) Oxalic acid
b) Acetic acid
c) Formic acid
d) Glyoxal.

78) Alkyne, C7H12, when reacted with alkaline KMnO4 followed by acidification with HCI gives a mixture of (CH3)2CHCOOH+CH3CH2COOH. The alkyne C7H12 is
a) 3-Hexyne
b) 2-Methyl-2-hexene
c) 2-Methyl-3-hexyne
d) 3-Methyl-2-hexyne.

79) An alkyne which will react with KMnO4 to give pyruvic acid is
a) Ethyne
b) Propyne
c) 1-Butyne
d) 2-Butyne.

80) Reductive ozonolysis of acetylene gives
a) Glyoxal
b) Oxalic acid
c) Acetic acid
d)

81) Reductive ozonolysis of propyne gives
a) 2-Oxopropanal
b) 2-Oxopropanoic acid
c)
d)

82) An alkyne which on ozonolysis gives two moles of acetic acid is
a) 1-Butyne
b) 2-Butyne
c) Methylacetylene
d) 3-Methyl-1-butyne.

83) Which of the following statements is correct ?
a) Alkynes are reduced less readily than alkenes
b) Alkynes are reduced more readily than alkenes
c) Both alkynes and alkenes are reduced with equal speeds
d) Alkynes cannot be reduced to alkene stage.

84) A gas which is used for the artificial ripening of fruits is
a) Methane
b) Ethane
c) Ethyne
d) Hydrogen

85) Ethylene is an unsaturated hydrocarbon which decolourises Br2/CCI4 and alkaline KMnO4 solutions. In contrast, benzene is highly unsaturated yet it does not give the above reactions. This is because
a)
b) All the carbon-carbon bond lengths in benzene are equal
c) Benzene is stabilized by resonance
d) Benzene is a planar molecule.

86) The class of reactions most commonly given by benzene is
a) Electrophilic addition
b) Nucleophilic substitution
c) Electrophilic substitution
d) Nucleophilic addition.

87) Benzene reacts with CI2 in presence of a halogen carrier to produce
a) Benzyl chloride
b) Benzal chloride
c) Chlorobenzene
d) Benzene hexachloride.

88) Benzene reacts with excess of chlorine in sunlight to form
a) Chlorobenzene
b) p-Dichlorobenzene
c) Hexachlorobenzene
d) Benzene hexachloride.

89) The presence of electron-donating groups in the benzene ring
a) Directs the new entrant to the m-position
b) Makes further substitution difficult
c) Directs the new entrant to o- and p positions.
d) Both(b) and (c)

90) An activating group
a) activates only o- and p-positions
b) deactivates m-position
c) activates o- and p-more than m-position
d) deactivates m-more than o-and p-positions.

91) A deactivating group
a) deactivates only o-and p-positions
b) deactivates m-position
c) deactivates o-and p-more than m-position
d) deactivates m-more than o-and p-positions.

92) Amongst the following, a moderately activating group is
a) -NHR
b)
c)
d)

93) Amongst the following, a weakly activating group is
a)
b)
c)
d)

94) The correct sequence for the activating power of a group in benzene is
a)
b)
c)
d)

95) The nitro group in the benzene ring is
a) Activating and o-, p-directing
b) Deactivating and m-directing
c) Deactivating and o, p-directing
d) Activating and m-directing.

96) In aniline, the – NH2 group
a) activates the benzene ring via both inductive and resonance effects
b) deactivates the benzene ring via both inductive and resonance effects
c) activates the benzene ring via the resonance effect and deactivates it via the inductive effect
d) activates the benzene ring via the inductive effect and deactivates it via the resonance effect.

97) Which of the following reacts fastest with Br2+ anhydrous AICI3 ?
a) Benzene
b) Nitrobenzene
c) Toluene
d) Anisole.

98) Benzenesulphonic acid is formed when benzene is treated with
a)
b)
c)
d) All the three above.

99) The effective electrophile in aromatic sulphonation is
a)
b)
c)
d)

100) Which of the following when treated with super heated steam under pressure gives benzene ?
a) Benzenesulphonic acid
b) Benzyl chloride
c) Bromobenzene
d) Nitrobenzene.


Answer

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