{"id":12802,"date":"2025-09-23T06:47:21","date_gmt":"2025-09-23T05:47:21","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12802"},"modified":"2025-10-22T10:33:59","modified_gmt":"2025-10-22T09:33:59","slug":"hydrocarbons-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/23\/hydrocarbons-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Hydrocarbons Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n

1. Hydrocarbons are compounds made up of:<\/mark><\/strong>
a) Carbon and oxygen
b) Carbon and hydrogen
c) Carbon and nitrogen
d) Carbon and sulphur
Answer:<\/strong> b) Carbon and hydrogen
Explanation:<\/strong> Hydrocarbons are organic compounds consisting only of carbon and hydrogen atoms.<\/p>\n\n\n\n

2. The simplest hydrocarbon is:
<\/mark><\/strong>a) Methane
b) Ethane
c) Propane
d) Acetylene
Answer:<\/strong> a) Methane
Explanation:<\/strong> Methane (CH\u2084) is the first member of alkanes.<\/p>\n\n\n\n

3. Alkanes are also called:
<\/mark><\/strong>a) Olefins
b) Paraffins
c) Aromatics
d) Acetylenes
Answer:<\/strong> b) Paraffins
Explanation:<\/strong> Alkanes are saturated hydrocarbons (CnH\u2082n+2), also called paraffins (little reactivity).<\/p>\n\n\n\n

4. General formula of alkanes is:
<\/mark><\/strong>a) CnH\u2082n
b) CnH\u2082n+2
c) CnH\u2082n\u20132
d) CnH\u2082n+1
Answer:<\/strong> b) CnH\u2082n+2
Explanation:<\/strong> Alkanes follow general formula CnH\u2082n+2.<\/p>\n\n\n\n

5. Ethane (C\u2082H\u2086) belongs to:
<\/mark><\/strong>a) Alkanes
b) Alkenes
c) Alkynes
d) Aromatics
Answer:<\/strong> a) Alkanes
Explanation:<\/strong> Ethane is a saturated hydrocarbon with single bonds only.<\/p>\n\n\n\n

6. Which alkane has 3 carbon atoms?
<\/mark><\/strong>a) Methane
b) Ethane
c) Propane
d) Butane
Answer:<\/strong> c) Propane
Explanation:<\/strong> Propane (C\u2083H\u2088) is the third member of alkanes.<\/p>\n\n\n\n

7. Butane is used in:
<\/mark><\/strong>a) Fertilizer industry
b) LPG as cooking fuel
c) Explosives
d) Plastics
Answer:<\/strong> b) LPG as cooking fuel
Explanation:<\/strong> LPG is mainly a mixture of propane and butane.<\/p>\n\n\n\n

8. Isomerism starts from which alkane?
<\/mark><\/strong>a) Methane
b) Ethane
c) Propane
d) Butane
Answer:<\/strong> d) Butane
Explanation:<\/strong> Butane (C\u2084H\u2081\u2080) has two isomers \u2013 n-butane and isobutane.<\/p>\n\n\n\n

9. Cycloalkanes have general formula:
<\/mark><\/strong>a) CnH\u2082n+2
b) CnH\u2082n
c) CnH\u2082n\u20132
d) CnH\u2082n+1
Answer:<\/strong> b) CnH\u2082n
Explanation:<\/strong> Cycloalkanes are ring hydrocarbons with general formula CnH\u2082n.<\/p>\n\n\n\n

10. The IUPAC name of isobutane is:
<\/mark><\/strong>a) 2-methylpropane
b) 2-methylbutane
c) 3-methylpentane
d) 2,2-dimethylpropane
Answer:<\/strong> a) 2-methylpropane
Explanation:<\/strong> Isobutane is a branched-chain isomer of butane.<\/p>\n\n\n\n

11. Alkanes are generally obtained from:
<\/mark><\/strong>a) Natural gas and petroleum
b) Coal
c) Air
d) Plants only
Answer:<\/strong> a) Natural gas and petroleum
Explanation:<\/strong> Natural gas contains methane, ethane, propane, and butane.<\/p>\n\n\n\n

12. The main constituent of natural gas is:
<\/mark><\/strong>a) Ethane
b) Methane
c) Propane
d) Butane
Answer:<\/strong> b) Methane
Explanation:<\/strong> Natural gas has ~80\u201390% methane.<\/p>\n\n\n\n

13. Which alkane is also known as marsh gas?
<\/mark><\/strong>a) Ethane
b) Propane
c) Methane
d) Butane
Answer:<\/strong> c) Methane
Explanation:<\/strong> Methane forms in marshes by decomposition of organic matter.<\/p>\n\n\n\n

14. Which alkane is used as a refrigerant in the form of liquefied gas?
<\/mark><\/strong>a) Methane
b) Ethane
c) Propane
d) Butane
Answer:<\/strong> c) Propane
Explanation:<\/strong> Propane is used in refrigeration and air-conditioning systems.<\/p>\n\n\n\n

15. Combustion of alkanes produces:
<\/mark><\/strong>a) CO only
b) CO\u2082 + H\u2082O
c) H\u2082 only
d) CO\u2082 + N\u2082
Answer:<\/strong> b) CO\u2082 + H\u2082O
Explanation:<\/strong> Complete combustion of alkanes \u2192 carbon dioxide + water.<\/p>\n\n\n\n

16. Incomplete combustion of alkanes produces:
<\/mark><\/strong>a) Only CO\u2082
b) Carbon monoxide and soot
c) Methanol
d) Oxygen
Answer:<\/strong> b) Carbon monoxide and soot
Explanation:<\/strong> Limited oxygen supply \u2192 CO + C (soot).<\/p>\n\n\n\n

17. The reaction of alkanes with chlorine in presence of sunlight is called:
<\/mark><\/strong>a) Addition reaction
b) Substitution reaction
c) Oxidation reaction
d) Hydrogenation
Answer:<\/strong> b) Substitution reaction
Explanation:<\/strong> Alkanes undergo free radical substitution with halogens.<\/p>\n\n\n\n

18. The main reaction of alkanes is:
<\/mark><\/strong>a) Addition
b) Substitution
c) Polymerization
d) Oxidation
Answer:<\/strong> b) Substitution
Explanation:<\/strong> Alkanes are saturated \u2192 undergo substitution.<\/p>\n\n\n\n

19. Pyrolysis of alkanes is:
<\/mark><\/strong>a) Heating in presence of oxygen
b) Heating in absence of air
c) Reaction with halogens
d) Oxidation
Answer:<\/strong> b) Heating in absence of air
Explanation:<\/strong> Pyrolysis = thermal decomposition \u2192 smaller alkanes + alkenes.<\/p>\n\n\n\n

20. The process of converting alkanes into aromatic hydrocarbons is:
<\/mark><\/strong>a) Hydrogenation
b) Aromatization
c) Isomerization
d) Substitution
Answer:<\/strong> b) Aromatization
Explanation:<\/strong> Aromatization converts alkanes into benzene\/toluene (catalysts used).<\/p>\n\n\n\n

21. The octane number of a fuel indicates:
<\/mark><\/strong>a) Density
b) Antiknocking property
c) Calorific value
d) Cost
Answer:<\/strong> b) Antiknocking property
Explanation:<\/strong> Higher octane number = better fuel efficiency.<\/p>\n\n\n\n

22. Iso-octane is used as:
<\/mark><\/strong>a) Reference fuel in octane number scale
b) Solvent
c) Explosive
d) Refrigerant
Answer:<\/strong> a) Reference fuel in octane number scale
Explanation:<\/strong> Iso-octane = 100 octane rating, reference standard.<\/p>\n\n\n\n

23. Knocking in petrol engines is reduced by adding:
<\/mark><\/strong>a) Lead tetraethyl
b) Alcohol
c) Acetone
d) Hydrogen
Answer:<\/strong> a) Lead tetraethyl
Explanation:<\/strong> Lead tetraethyl (historically) improved octane rating.<\/p>\n\n\n\n

24. Which alkane is used in the production of carbon black?
<\/mark><\/strong>a) Methane
b) Ethane
c) Acetylene
d) Natural gas
Answer:<\/strong> d) Natural gas
Explanation:<\/strong> Methane-rich natural gas is burnt in limited oxygen \u2192 carbon black (tyres, inks).<\/p>\n\n\n\n

25. Higher alkanes are generally found in:
<\/mark><\/strong>a) Natural gas
b) Kerosene and diesel fractions of petroleum
c) Coal gas
d) Air
Answer:<\/strong> b) Kerosene and diesel fractions of petroleum
Explanation:<\/strong> Higher alkanes (C\u2081\u2080\u2013C\u2081\u2086) are in kerosene, diesel, and lubricating oils.<\/p>\n\n\n\n

26. Alkenes are also called:
<\/mark><\/strong>a) Paraffins
b) Olefins
c) Aromatics
d) Acetylenes
Answer:<\/strong> b) Olefins
Explanation:<\/strong> Alkenes (CnH\u2082n) are unsaturated hydrocarbons with double bonds, called olefins.<\/p>\n\n\n\n

27. General formula of alkenes is:
<\/mark><\/strong>a) CnH\u2082n+2
b) CnH\u2082n
c) CnH\u2082n\u20132
d) CnH\u2082n\u20131
Answer:<\/strong> b) CnH\u2082n
Explanation:<\/strong> Alkenes have one double bond, general formula CnH\u2082n.<\/p>\n\n\n\n

28. The first member of alkenes is:
<\/mark><\/strong>a) Methene
b) Ethene
c) Propene
d) Butene
Answer:<\/strong> b) Ethene
Explanation:<\/strong> Ethene (C\u2082H\u2084) is the simplest alkene.<\/p>\n\n\n\n

29. The IUPAC name of propylene is:
<\/mark><\/strong>a) But-1-ene
b) Ethene
c) Prop-1-ene
d) But-2-ene
Answer:<\/strong> c) Prop-1-ene
Explanation:<\/strong> Propylene is prop-1-ene (CH\u2082=CH\u2013CH\u2083).<\/p>\n\n\n\n

30. Alkenes mainly undergo:
<\/mark><\/strong>a) Substitution reactions
b) Addition reactions
c) Elimination reactions
d) Oxidation reactions only
Answer:<\/strong> b) Addition reactions
Explanation:<\/strong> Double bonds make alkenes reactive towards electrophilic addition.<\/p>\n\n\n\n

31. Which of the following is an addition reaction of ethene?
<\/mark><\/strong>a) Ethene + H\u2082 \u2192 Ethane
b) Ethene + Cl\u2082 \u2192 Dichloroethane
c) Ethene + HCl \u2192 Chloroethane
d) All of the above
Answer:<\/strong> d) All of the above
Explanation:<\/strong> Alkenes undergo hydrogenation and halogenation addition reactions.<\/p>\n\n\n\n

32. The addition of HCl to alkenes follows:
<\/mark><\/strong>a) Markovnikov\u2019s rule
b) Hund\u2019s rule
c) Le Chatelier\u2019s principle
d) Pauli\u2019s rule
Answer:<\/strong> a) Markovnikov\u2019s rule
Explanation:<\/strong> According to Markovnikov\u2019s rule, H attaches to carbon with more hydrogens.<\/p>\n\n\n\n

33. Anti-Markovnikov addition occurs in the presence of:
<\/mark><\/strong>a) Peroxides
b) Acids
c) Alkali metals
d) Bases
Answer:<\/strong> a) Peroxides
Explanation:<\/strong> With peroxides, HBr adds to alkenes in anti-Markovnikov fashion.<\/p>\n\n\n\n

34. Ethene is used in:<\/strong>
<\/mark>a) Welding
b) Ripening of fruits
c) Rocket fuel
d) Anaesthesia
Answer:<\/strong> b) Ripening of fruits
Explanation:<\/strong> Ethene is a plant hormone that induces fruit ripening.<\/p>\n\n\n\n

35. Which reagent is used to test unsaturation in hydrocarbons?
<\/mark><\/strong>a) Bromine water
b) Acidified KMnO\u2084
c) Baeyer’s reagent
d) All of these
Answer:<\/strong> d) All of these
Explanation:<\/strong> Bromine water and Baeyer\u2019s reagent (KMnO\u2084) decolorize with alkenes\/alkynes.<\/p>\n\n\n\n

36. Alkenes on oxidation with cold dilute KMnO\u2084 give:<\/strong>
<\/mark>a) Alcohol
b) Diol (glycol)
c) Aldehyde
d) Ketone
Answer:<\/strong> b) Diol (glycol)
Explanation:<\/strong> Mild oxidation forms glycols (cis-diols).<\/p>\n\n\n\n

37. Ozonolysis of alkenes gives:
<\/mark><\/strong>a) Alkanes
b) Alcohols
c) Aldehydes and ketones
d) Acids
Answer:<\/strong> c) Aldehydes and ketones
Explanation:<\/strong> Ozonolysis cleaves double bonds into carbonyl compounds.<\/p>\n\n\n\n

38. Alkynes are also called:
<\/mark><\/strong>a) Acetylenes
b) Olefins
c) Paraffins
d) Aromatics
Answer:<\/strong> a) Acetylenes
Explanation:<\/strong> Alkynes (CnH\u2082n\u20132) with triple bonds are called acetylenes.<\/p>\n\n\n\n

39. General formula of alkynes is:
<\/mark><\/strong>a) CnH\u2082n+2
b) CnH\u2082n
c) CnH\u2082n\u20132
d) CnH\u2082n\u20131
Answer:<\/strong> c) CnH\u2082n\u20132
Explanation:<\/strong> Alkynes contain one triple bond, general formula CnH\u2082n\u20132.<\/p>\n\n\n\n

40. The first member of alkynes is:
<\/mark><\/strong>a) Ethyne
b) Methyne
c) Propyne
d) Butyne
Answer:<\/strong> a) Ethyne
Explanation:<\/strong> Ethyne (C\u2082H\u2082), commonly called acetylene, is the first alkyne.<\/p>\n\n\n\n

41. Propyne has molecular formula:
<\/mark><\/strong>a) C\u2083H\u2084
b) C\u2083H\u2086
c) C\u2083H\u2088
d) C\u2083H\u2082
Answer:<\/strong> a) C\u2083H\u2084
Explanation:<\/strong> Propyne (HC\u2261C\u2013CH\u2083) has 3 carbons and 4 hydrogens.<\/p>\n\n\n\n

42. Alkynes mainly undergo:
<\/mark><\/strong>a) Addition reactions
b) Substitution reactions
c) Oxidation only
d) Polymerization only
Answer:<\/strong> a) Addition reactions
Explanation:<\/strong> Alkynes add halogens, hydrogen, and acids across triple bonds.<\/p>\n\n\n\n

43. Hydrogenation of ethyne gives:
<\/mark><\/strong>a) Ethene (partial) \u2192 Ethane (complete)
b) Ethane only
c) Methane
d) Propane
Answer:<\/strong> a) Ethene (partial) \u2192 Ethane (complete)
Explanation:<\/strong> Ethyne + H\u2082 \u2192 ethene \u2192 ethane.<\/p>\n\n\n\n

44. Ethyne reacts with chlorine to form:
<\/mark><\/strong>a) Dichloroethane
b) Tetrachloroethane
c) Both (depending on conditions)
d) None
Answer:<\/strong> c) Both
Explanation:<\/strong> Addition of 1 mole Cl\u2082 \u2192 dichloroethene; 2 moles Cl\u2082 \u2192 tetrachloroethane.<\/p>\n\n\n\n

45. Which alkyne is used in oxy-acetylene welding?
<\/mark><\/strong>a) Methyne
b) Ethyne
c) Propyne
d) Butyne
Answer:<\/strong> b) Ethyne
Explanation:<\/strong> Ethyne burns in oxygen to give high temperature flame (\u2248 3500\u00b0C).<\/p>\n\n\n\n

46. Ethyne with ammoniacal AgNO\u2083 gives:
<\/mark><\/strong>a) White precipitate
b) Yellow precipitate
c) Brown precipitate
d) No reaction
Answer:<\/strong> a) White precipitate
Explanation:<\/strong> Terminal alkynes form white precipitate of silver acetylide with AgNO\u2083.<\/p>\n\n\n\n

47. Ethyne with ammoniacal Cu\u2082Cl\u2082 gives:
<\/mark><\/strong>a) Red precipitate
b) Yellow precipitate
c) White precipitate
d) Green precipitate
Answer:<\/strong> a) Red precipitate
Explanation:<\/strong> Terminal alkynes give red precipitate of copper acetylide.<\/p>\n\n\n\n

48. Ozonolysis of alkynes gives:<\/mark><\/strong>
a) Alkanes
b) Alcohols
c) Carboxylic acids
d) Ketones
Answer:<\/strong> c) Carboxylic acids
Explanation:<\/strong> Triple bond cleavage produces acids.<\/p>\n\n\n\n

49. Ethyne reacts with water in presence of H\u2082SO\u2084 and Hg\u00b2\u207a catalyst to form:
<\/mark><\/strong>a) Ethanol
b) Acetaldehyde
c) Acetone
d) Acetic acid
Answer:<\/strong> b) Acetaldehyde
Explanation:<\/strong> Hydration of ethyne \u2192 vinyl alcohol \u2192 tautomerizes to acetaldehyde.<\/p>\n\n\n\n

50. Which test distinguishes alkanes from alkenes and alkynes?
<\/mark><\/strong>a) Bromine water test
b) Flame test
c) Neutralization test
d) Distillation
Answer:<\/strong> a) Bromine water test
Explanation:<\/strong> Alkenes\/alkynes decolorize bromine water; alkanes do not.<\/p>\n\n\n\n

51. Aromatic hydrocarbons contain:
<\/mark><\/strong>a) Only single bonds
b) Alternating single and double bonds in a ring
c) Only triple bonds
d) Open chain carbon atoms
Answer:<\/strong> b) Alternating single and double bonds in a ring
Explanation:<\/strong> Aromatics follow Huckel\u2019s rule with delocalized \u03c0-electrons.<\/p>\n\n\n\n

52. Benzene has the molecular formula:
<\/mark><\/strong>a) C\u2086H\u2081\u2082
b) C\u2086H\u2086
c) C\u2086H\u2081\u2080
d) C\u2086H\u2088
Answer:<\/strong> b) C\u2086H\u2086
Explanation:<\/strong> Benzene has 6 carbons and 6 hydrogens, highly unsaturated but stable.<\/p>\n\n\n\n

53. The Kekul\u00e9 structure of benzene has:
<\/mark><\/strong>a) Alternating double and single bonds
b) All single bonds
c) All double bonds
d) No bonds
Answer:<\/strong> a) Alternating double and single bonds
Explanation:<\/strong> Kekul\u00e9 proposed resonance structures for benzene.<\/p>\n\n\n\n

54. Benzene is considered aromatic because it follows:<\/strong>
<\/mark>a) Le Chatelier\u2019s principle
b) Hund\u2019s rule
c) Huckel\u2019s rule (4n + 2 \u03c0 electrons)
d) Pauli\u2019s principle
Answer:<\/strong> c) Huckel\u2019s rule
Explanation:<\/strong> Benzene has 6 \u03c0-electrons (n=1) \u2192 aromatic stability.<\/p>\n\n\n\n

55. Which of the following is a property of benzene?
<\/mark><\/strong>a) Highly reactive like alkenes
b) Undergoes substitution reactions
c) Always undergoes addition reactions
d) Combines explosively with water
Answer:<\/strong> b) Undergoes substitution reactions
Explanation:<\/strong> Aromatics undergo electrophilic substitution instead of addition (stability retained).<\/p>\n\n\n\n

56. The main reaction of benzene is:
<\/mark><\/strong>a) Addition
b) Substitution
c) Elimination
d) Polymerization
Answer:<\/strong> b) Substitution
Explanation:<\/strong> Benzene maintains aromaticity \u2192 undergoes electrophilic substitution.<\/p>\n\n\n\n

57. Nitration of benzene gives:
<\/mark><\/strong>a) Aniline
b) Nitrobenzene
c) Phenol
d) Benzaldehyde
Answer:<\/strong> b) Nitrobenzene
Explanation:<\/strong> Benzene + HNO\u2083\/H\u2082SO\u2084 \u2192 nitrobenzene.<\/p>\n\n\n\n

58. Sulphonation of benzene gives:
<\/mark><\/strong>a) Benzaldehyde
b) Benzenesulphonic acid
c) Nitrobenzene
d) Benzyl alcohol
Answer:<\/strong> b) Benzenesulphonic acid
Explanation:<\/strong> Benzene + SO\u2083\/H\u2082SO\u2084 \u2192 benzenesulphonic acid.<\/p>\n\n\n\n

59. Friedel\u2013Crafts alkylation uses:
<\/mark><\/strong>a) AlCl\u2083 catalyst
b) H\u2082SO\u2084 catalyst
c) Pt catalyst
d) Cu catalyst
Answer:<\/strong> a) AlCl\u2083 catalyst
Explanation:<\/strong> Alkyl halide + benzene \u2192 alkylbenzene (catalyst AlCl\u2083).<\/p>\n\n\n\n

60. Friedel\u2013Crafts acylation introduces:
<\/mark><\/strong>a) Nitro group
b) Alkyl group
c) Acyl group (\u2013COR)
d) Sulphonic group
Answer:<\/strong> c) Acyl group (\u2013COR)
Explanation:<\/strong> Acyl halide + benzene + AlCl\u2083 \u2192 acylbenzene.<\/p>\n\n\n\n

61. Toluene is:
<\/mark><\/strong>a) Methylbenzene
b) Ethylbenzene
c) Dimethylbenzene
d) Benzyl alcohol
Answer:<\/strong> a) Methylbenzene
Explanation:<\/strong> Toluene has a \u2013CH\u2083 group attached to benzene.<\/p>\n\n\n\n

62. On nitration, toluene gives mainly:
<\/mark><\/strong>a) Ortho- and para-nitrotoluene
b) Meta-nitrotoluene
c) Benzonitrile
d) Dinitrobenzene
Answer:<\/strong> a) Ortho- and para-nitrotoluene
Explanation:<\/strong> \u2013CH\u2083 group is an ortho\/para directing group.<\/p>\n\n\n\n

63. Oxidation of toluene with KMnO\u2084 gives:
<\/mark><\/strong>a) Benzyl alcohol
b) Benzaldehyde
c) Benzoic acid
d) Phenol
Answer:<\/strong> c) Benzoic acid
Explanation:<\/strong> Side chain oxidation converts \u2013CH\u2083 into \u2013COOH.<\/p>\n\n\n\n

64. Xylene is:
<\/mark><\/strong>a) Dimethylbenzene
b) Nitrobenzene
c) Benzoic acid
d) Aniline
Answer:<\/strong> a) Dimethylbenzene
Explanation:<\/strong> Xylenes are isomers of C\u2086H\u2084(CH\u2083)\u2082.<\/p>\n\n\n\n

65. The number of xylene isomers is:
<\/mark><\/strong>a) 2
b) 3
c) 4
d) 5
Answer:<\/strong> b) 3
Explanation:<\/strong> o-xylene, m-xylene, and p-xylene are possible.<\/p>\n\n\n\n

66. Naphthalene consists of:<\/strong>
<\/mark>a) One benzene ring
b) Two fused benzene rings
c) Three benzene rings
d) A benzene + cyclohexane ring
Answer:<\/strong> b) Two fused benzene rings
Explanation:<\/strong> Naphthalene has two fused aromatic rings.<\/p>\n\n\n\n

67. Anthracene contains:<\/mark><\/strong>
a) 2 benzene rings
b) 3 linearly fused benzene rings
c) 4 fused benzene rings
d) None
Answer:<\/strong> b) 3 linearly fused benzene rings
Explanation:<\/strong> Anthracene has three fused benzene rings.<\/p>\n\n\n\n

68. Phenanthrene contains:<\/mark><\/strong>
a) 2 fused rings
b) 3 fused rings (angular)
c) 4 fused rings
d) 5 fused rings
Answer:<\/strong> b) 3 fused rings (angular)
Explanation:<\/strong> Phenanthrene has 3 fused benzene rings in an angular structure.<\/p>\n\n\n\n

69. Benzene is less reactive towards addition reactions because:<\/mark><\/strong>
a) It has high resonance energy
b) It is saturated
c) It has weak bonds
d) It has high reactivity
Answer:<\/strong> a) It has high resonance energy
Explanation:<\/strong> Resonance stabilizes benzene, preventing addition.<\/p>\n\n\n\n

70. Benzene undergoes chlorination in presence of FeCl\u2083 to give:<\/strong><\/mark>
a) Chlorobenzene
b) Benzyl chloride
c) Dichlorobenzene
d) Benzene hexachloride
Answer:<\/strong> a) Chlorobenzene
Explanation:<\/strong> Substitution gives chlorobenzene.<\/p>\n\n\n\n

71. Halogenation of benzene requires:
<\/mark><\/strong>a) UV light
b) Lewis acid catalyst (FeCl\u2083, AlCl\u2083)
c) H\u2082SO\u2084
d) NaOH
Answer:<\/strong> b) Lewis acid catalyst (FeCl\u2083, AlCl\u2083)
Explanation:<\/strong> Catalysts polarize halogens, enabling substitution.<\/p>\n\n\n\n

72. TNT (trinitrotoluene) is prepared from toluene by:
<\/mark><\/strong>a) Sulphonation
b) Nitration
c) Halogenation
d) Oxidation
Answer:<\/strong> b) Nitration
Explanation:<\/strong> Toluene nitrated to 2,4,6-trinitrotoluene (explosive).<\/p>\n\n\n\n

73. The product of sulphonation of naphthalene at low temperature is:
<\/mark><\/strong>a) \u03b1-naphthalenesulphonic acid
b) \u03b2-naphthalenesulphonic acid
c) Nitro-naphthalene
d) Naphthol
Answer:<\/strong> a) \u03b1-naphthalenesulphonic acid
Explanation:<\/strong> Low temperature favours \u03b1-substitution.<\/p>\n\n\n\n

74. The product of sulphonation of naphthalene at high temperature is:
<\/mark><\/strong>a) \u03b1-naphthalenesulphonic acid
b) \u03b2-naphthalenesulphonic acid
c) Dinitronaphthalene
d) Anthracene
Answer:<\/strong> b) \u03b2-naphthalenesulphonic acid
Explanation:<\/strong> High temperature favours \u03b2-substitution.<\/p>\n\n\n\n

75. The most stable aromatic hydrocarbon among the following is:
<\/mark><\/strong>a) Benzene
b) Toluene
c) Anthracene
d) Naphthalene
Answer:<\/strong> a) Benzene
Explanation:<\/strong> Benzene has maximum resonance stability compared to fused aromatics.<\/p>\n\n\n\n

76. The main source of hydrocarbons is:
<\/mark><\/strong>a) Air
b) Water
c) Petroleum and natural gas
d) Soil
Answer:<\/strong> c) Petroleum and natural gas
Explanation:<\/strong> Hydrocarbons are extracted mainly from crude oil and natural gas reserves.<\/p>\n\n\n\n

77. Petroleum is a mixture of:<\/strong>
<\/mark>a) Alkanes only
b) Alkanes, cycloalkanes, and aromatics
c) Alcohols and acids
d) Esters
Answer:<\/strong> b) Alkanes, cycloalkanes, and aromatics
Explanation:<\/strong> Crude oil contains various hydrocarbons, refined into fuels and chemicals.<\/p>\n\n\n\n

78. The process of separating petroleum into useful fractions is:
<\/mark><\/strong>a) Cracking
b) Distillation
c) Refining
d) Fractional distillation
Answer:<\/strong> d) Fractional distillation
Explanation:<\/strong> Petroleum is separated by fractional distillation based on boiling points.<\/p>\n\n\n\n

79. LPG is a mixture of:
<\/mark><\/strong>a) Methane and ethane
b) Propane and butane
c) Ethylene and acetylene
d) Benzene and toluene
Answer:<\/strong> b) Propane and butane
Explanation:<\/strong> LPG (cooking gas) contains mainly propane and butane.<\/p>\n\n\n\n

80. CNG mainly contains:<\/mark><\/strong>
a) Methane
b) Ethane
c) Propane
d) Butane
Answer:<\/strong> a) Methane
Explanation:<\/strong> Compressed Natural Gas is methane-rich and a clean fuel.<\/p>\n\n\n\n

81. Which hydrocarbon is used for welding purposes?
<\/mark><\/strong>a) Methane
b) Ethane
c) Ethyne
d) Propane
Answer:<\/strong> c) Ethyne
Explanation:<\/strong> Ethyne (acetylene) burns in oxygen to give a hot flame (~3500\u00b0C).<\/p>\n\n\n\n

82. Petrol is obtained from:
<\/mark><\/strong>a) Light fraction of petroleum
b) Heavy fraction of petroleum
c) Coal tar
d) Natural gas only
Answer:<\/strong> a) Light fraction of petroleum
Explanation:<\/strong> Petrol (gasoline) comes from lighter fractions during refining.<\/p>\n\n\n\n

83. Kerosene belongs to:
<\/mark><\/strong>a) Lighter fractions of petroleum
b) Middle fractions of petroleum
c) Heavy fractions of petroleum
d) Residue
Answer:<\/strong> b) Middle fractions of petroleum
Explanation:<\/strong> Kerosene is in the middle distillate range.<\/p>\n\n\n\n

84. Diesel is obtained from:
<\/mark><\/strong>a) Residue
b) Middle fraction
c) Light fraction
d) Gaseous fraction
Answer:<\/strong> b) Middle fraction
Explanation:<\/strong> Diesel is heavier than kerosene but lighter than lubricating oils.<\/p>\n\n\n\n

85. The heaviest fraction obtained from petroleum distillation is:
<\/mark><\/strong>a) Petrol
b) Diesel
c) Bitumen
d) Kerosene
Answer:<\/strong> c) Bitumen
Explanation:<\/strong> Bitumen (asphalt) is the residue after fractional distillation.<\/p>\n\n\n\n

86. The process of breaking higher hydrocarbons into lower ones is:
<\/mark><\/strong>a) Polymerization
b) Cracking
c) Distillation
d) Refining
Answer:<\/strong> b) Cracking
Explanation:<\/strong> Cracking breaks heavy hydrocarbons into lighter alkanes\/alkenes.<\/p>\n\n\n\n

87. Which process improves the octane number of petrol?
<\/mark><\/strong>a) Cracking
b) Reforming
c) Hydrogenation
d) Distillation
Answer:<\/strong> b) Reforming
Explanation:<\/strong> Catalytic reforming increases branching \u2192 higher octane rating.<\/p>\n\n\n\n

88. Polymerization of ethene gives:
<\/mark><\/strong>a) Polyethene
b) Polypropylene
c) Polystyrene
d) Teflon
Answer:<\/strong> a) Polyethene
Explanation:<\/strong> Ethene polymerizes to form polyethylene (plastic bags, bottles).<\/p>\n\n\n\n

89. Polymerization of propene gives:
<\/mark><\/strong>a) Polyethene
b) Polypropylene
c) Polystyrene
d) PVC
Answer:<\/strong> b) Polypropylene
Explanation:<\/strong> Propene polymerizes to polypropylene (ropes, packaging).<\/p>\n\n\n\n

90. Polymerization of vinyl chloride gives:
<\/mark><\/strong>a) PVC
b) Polyethene
c) Polypropylene
d) Nylon
Answer:<\/strong> a) PVC
Explanation:<\/strong> Vinyl chloride \u2192 polyvinyl chloride (PVC) used in pipes, insulation.<\/p>\n\n\n\n

91. Polymerization of styrene gives:
<\/mark><\/strong>a) Nylon
b) Teflon
c) Polystyrene
d) Polyester
Answer:<\/strong> c) Polystyrene
Explanation:<\/strong> Styrene polymerizes into polystyrene (disposable cups, packaging).<\/p>\n\n\n\n

92. Teflon is obtained by polymerization of:
<\/mark><\/strong>a) Ethene
b) Propene
c) Tetrafluoroethene
d) Vinyl chloride
Answer:<\/strong> c) Tetrafluoroethene
Explanation:<\/strong> Teflon (non-stick coating) is PTFE from tetrafluoroethene.<\/p>\n\n\n\n

93. The main hydrocarbon in coal gas is:
<\/mark><\/strong>a) Methane
b) Hydrogen
c) Carbon monoxide
d) A mixture of all
Answer:<\/strong> d) A mixture of all
Explanation:<\/strong> Coal gas has CH\u2084, H\u2082, and CO.<\/p>\n\n\n\n

94. Water gas is a mixture of:
<\/mark><\/strong>a) CO and H\u2082
b) CO\u2082 and H\u2082
c) CH\u2084 and CO\u2082
d) CO and CH\u2084
Answer:<\/strong> a) CO and H\u2082
Explanation:<\/strong> Water gas = CO + H\u2082, used as fuel.<\/p>\n\n\n\n

95. Producer gas is a mixture of:
<\/mark><\/strong>a) CO + H\u2082
b) CO + N\u2082
c) H\u2082 + CH\u2084
d) CO\u2082 + N\u2082
Answer:<\/strong> b) CO + N\u2082
Explanation:<\/strong> Producer gas is CO + N\u2082 from coal with air.<\/p>\n\n\n\n

96. Coal tar contains:
<\/mark><\/strong>a) Alkanes only
b) Aromatic hydrocarbons like benzene, naphthalene, anthracene
c) Alcohols only
d) Acids only
Answer:<\/strong> b) Aromatic hydrocarbons
Explanation:<\/strong> Coal tar is a source of aromatic hydrocarbons and dyes.<\/p>\n\n\n\n

97. The high calorific value of hydrocarbons is due to:
<\/mark><\/strong>a) Presence of oxygen
b) Presence of hydrogen and carbon bonds
c) Presence of nitrogen
d) Presence of sulphur
Answer:<\/strong> b) Presence of hydrogen and carbon bonds
Explanation:<\/strong> Hydrocarbons release large energy on combustion (CO\u2082 + H\u2082O).<\/p>\n\n\n\n

98. Which hydrocarbon derivative is used as anaesthetic (\u201claughing gas\u201d)?
<\/mark><\/strong>a) CO
b) N\u2082O
c) CHCl\u2083
d) C\u2082H\u2082
Answer:<\/strong> b) N\u2082O
Explanation:<\/strong> Nitrous oxide (not a hydrocarbon itself but derivative) is used in anaesthesia.<\/p>\n\n\n\n

99. Which hydrocarbon is known as \u201cdry ice\u201d when solidified?
<\/mark><\/strong>a) Methane
b) Carbon dioxide
c) Ethane
d) Butane
Answer:<\/strong> b) Carbon dioxide
Explanation:<\/strong> Though CO\u2082 is not a hydrocarbon, it is an important carbon compound often studied alongside fuels.<\/p>\n\n\n\n

100. The main environmental effect of burning hydrocarbons is:
<\/strong><\/mark>a) Ozone depletion
b) Air pollution and greenhouse effect (CO\u2082, CO emissions)
c) Soil fertility increase
d) Acid rain only
Answer:<\/strong> b) Air pollution and greenhouse effect
Explanation:<\/strong> Hydrocarbon combustion \u2192 CO\u2082 (global warming), CO, NOx (pollution).<\/p>\n","protected":false},"excerpt":{"rendered":"

1. Hydrocarbons are compounds made up of:a) Carbon and oxygenb) Carbon and hydrogenc) Carbon and nitrogend) Carbon and sulphurAnswer: b) Carbon and hydrogenExplanation: Hydrocarbons are organic compounds consisting only of carbon and hydrogen atoms. 2. The simplest hydrocarbon is:a) Methaneb) Ethanec) Propaned) AcetyleneAnswer: a) MethaneExplanation: Methane (CH\u2084) is the first member of alkanes. 3. Alkanes<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[16069,15994,15999,16000,16071,16073,16007,15886,15892,15876,15898,15901,15887,15899,15879,15883,16006,16076,15998,16074,10978,15997,4029,15897,5649,5623,15927,16001,15900,16070,15896,16072,16075,15894],"class_list":{"0":"post-12802","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-chemistry","7":"tag-addition-reactions","8":"tag-alkanes","9":"tag-alkenes","10":"tag-alkynes","11":"tag-aromatic-hydrocarbons","12":"tag-bonding-in-hydrocarbons","13":"tag-chemical-reactions","14":"tag-chemistry-formulas","15":"tag-chemistry-learning","16":"tag-chemistry-mcqs","17":"tag-chemistry-preparation-material","18":"tag-chemistry-questions-and-answers","19":"tag-chemistry-quiz","20":"tag-chemistry-revision","21":"tag-chemistry-study-material","22":"tag-competitive-exam-chemistry","23":"tag-functional-groups","24":"tag-hydrocarbon-applications","25":"tag-hydrocarbons","26":"tag-hydrocarbons-problems","27":"tag-hydrocarbons-top-100-mcqs-with-answer-and-explanation","28":"tag-isomerism","29":"tag-mcqs-adda","30":"tag-mcqs-for-chemistry-exam","31":"tag-mcqs-for-pc-psi-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","32":"tag-mcqs-for-sda-fda-pdo-vao-banking-kas-ias-ssc-gd-ssc-chsl-ssc-cgl-for-all-compitative-exams","33":"tag-molecular-structure","34":"tag-organic-chemistry","35":"tag-psc-chemistry-mcqs","36":"tag-saturated-hydrocarbons","37":"tag-ssc-chemistry-mcqs","38":"tag-substitution-reactions","39":"tag-unsaturated-hydrocarbons","40":"tag-upsc-chemistry-mcqs"},"_links":{"self":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12802","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/comments?post=12802"}],"version-history":[{"count":3,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12802\/revisions"}],"predecessor-version":[{"id":12955,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/posts\/12802\/revisions\/12955"}],"wp:attachment":[{"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/media?parent=12802"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/categories?post=12802"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mcqsadda.com\/index.php\/wp-json\/wp\/v2\/tags?post=12802"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}