Haloalkanes and Haloarenes MCQ

Haloalkanes and Haloarenes MCQ. These 100 Multiple Choice Questions with Answer and Explanation will help you score full marks in your class 12 Chemistry exam.

Introduction to Haloalkanes and Haloarenes

Definition and Basic Concepts (MCQ 1 to 3)

1. What is the primary difference between haloalkanes and haloarenes?A. Haloalkanes contain halogen attached to sp² hybridized carbonB. Haloarenes contain halogen attached to sp³ hybridized carbonC. Haloalkanes contain halogen attached to sp³ hybridized carbonD. Haloarenes contain halogen attached to sp³ hybridized carbon[Answer: C. Haloalkanes contain halogen attached to sp³ hybridized carbon while haloarenes contain halogen attached to sp² hybridized carbon. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

2. Which of the following is an example of a haloalkane?A. ChlorobenzeneB. ChloroformC. BromobenzeneD. Iodobenzene[Answer: B. Chloroform is a haloalkane, while the others are haloarenes. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

3. Which of the following is used as an anesthetic during surgery?A. ChloroformB. HalothaneC. MethanolD. Ethanol[Answer: B. Halothane is used as an anesthetic during surgery. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Classification of Haloalkanes and Haloarenes

On the Basis of Number of Halogen Atoms (MCQ 4 to 9)

4. Which of the following is a polyhalogen compound?A. Methylene chlorideB. ChlorobenzeneC. DDTD. Ethyl chloride[Answer: C. DDT is a polyhalogen compound as it contains more than one halogen atom. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

5. Which of the following is a monohalogen compound?A. BromoformB. ChloromethaneC. Carbon tetrachlorideD. Freon[Answer: B. Chloromethane is a monohalogen compound. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Based on Hybridization of Carbon

6. In which type of compound is the halogen attached to an sp³ hybridized carbon?A. Alkyl halideB. Aryl halideC. Vinylic halideD. Allylic halide[Answer: A. In alkyl halides, halogen is attached to an sp³ hybridized carbon. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

7. Which of the following has a halogen attached to a carbon-carbon double bond?A. Allylic halideB. Vinylic halideC. Benzylic halideD. Alkyl halide[Answer: B. Vinylic halides have halogen attached to an sp² hybridized carbon of a double bond. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

8. In allylic halides, the halogen atom is bonded to which type of carbon?A. Carbon-carbon single bondB. Carbon-carbon double bondC. Carbon adjacent to a double bondD. Aromatic ring[Answer: C. In allylic halides, halogen is bonded to the carbon adjacent to a carbon-carbon double bond. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

9. Which type of compound contains a halogen bonded to an aromatic ring?A. Allylic halideB. Benzylic halideC. Vinylic halideD. Aryl halide[Answer: D. Aryl halides contain halogen bonded directly to the aromatic ring. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Nomenclature

Common and IUPAC Naming Rules (MCQ 10 to 14)

10. What is the IUPAC name of CH₃CH₂Cl?A. Ethyl chlorideB. ChloroethaneC. Methyl chlorideD. Chloromethane[Answer: B. The IUPAC name of CH₃CH₂Cl is chloroethane. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

11. Which of the following is a common name for 2-Chloropropane?A. Isopropyl chlorideB. Methyl chlorideC. Propyl chlorideD. Ethyl chloride[Answer: A. The common name for 2-Chloropropane is isopropyl chloride. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

12. What is the IUPAC name of CH₃CH₂CH₂Br?A. Propyl bromideB. BromoethaneC. BromopropaneD. Isopropyl bromide[Answer: C. The IUPAC name of CH₃CH₂CH₂Br is bromopropane. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

13. Which prefix is used for halogen-substituted hydrocarbons in IUPAC nomenclature?A. ChloroB. HaloC. HydroD. Meth[Answer: B. “Halo” is used as a prefix for halogen-substituted hydrocarbons in IUPAC nomenclature. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

14. What is the IUPAC name of (CH₃)₃CCl?A. Isobutyl chlorideB. Tert-butyl chlorideC. 2-Methylpropyl chlorideD. 1-Chloropropane[Answer: B. The IUPAC name of (CH₃)₃CCl is tert-butyl chloride. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Preparation of Haloalkanes and Haloarenes

From Alcohols (MCQ 15 to 18)

15. Which reagent is preferred for preparing alkyl halides from alcohols due to the formation of gaseous byproducts?A. PCl₅B. SOCl₂C. HClD. ZnCl₂[Answer: B. SOCl₂ is preferred as it forms alkyl halides along with gaseous byproducts SO₂ and HCl. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

16. What catalyst is required for the reaction of primary and secondary alcohols with HCl to produce alkyl halides?A. ZnCl₂B. PCl₃C. AlCl₃D. SOCl₂[Answer: A. ZnCl₂ is required as a catalyst when primary and secondary alcohols react with HCl. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

17. Which reaction condition is needed for converting tertiary alcohols to alkyl halides using HCl?A. Heat with ZnCl₂B. Heat with PCl₅C. Shake with concentrated HCl at room temperatureD. Treat with SOCl₂ at high temperature[Answer: C. Tertiary alcohols react with concentrated HCl at room temperature. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

18. What is the order of reactivity of alcohols with halogen acids?A. 3° > 1° > 2°B. 1° > 2° > 3°C. 3° > 2° > 1°D. 2° > 1° > 3°[Answer: C. The order of reactivity of alcohols with halogen acids is 3° > 2° > 1°. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

From Hydrocarbons (MCQ 19 to 23)

19. Which method is used to prepare alkyl halides from alkanes?A. Free radical halogenationB. Electrophilic substitutionC. Nucleophilic substitutionD. Dehydration[Answer: A. Free radical halogenation is used to prepare alkyl halides from alkanes. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

20. In free radical halogenation, which halogen is typically more selective for the formation of alkyl halides?A. ChlorineB. BromineC. FluorineD. Iodine[Answer: B. Bromine is more selective in free radical halogenation, leading to fewer side reactions. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

21. What type of reaction occurs when an alkene reacts with a halogen to form a dihalide?A. Addition reactionB. Substitution reactionC. Elimination reactionD. Hydrolysis[Answer: A. Addition reaction occurs when an alkene reacts with a halogen to form a dihalide. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

22. What is the major product of propene reacting with HBr according to Markovnikov’s rule?A. 1-BromopropaneB. 2-BromopropaneC. Allyl bromideD. Dibromopropane[Answer: B. 2-Bromopropane is the major product following Markovnikov’s rule. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

23. Which test detects the presence of a carbon-carbon double bond using bromine?A. Swarts reactionB. Wurtz reactionC. Bromine water testD. Finkelstein reaction[Answer: C. Bromine water test detects the presence of carbon-carbon double bonds. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Halogen Exchange (MCQ 24 to 26)

24. Which reaction is used to exchange a halide for iodine using dry acetone?A. Finkelstein reactionB. Swarts reactionC. Wurtz reactionD. Electrophilic substitution[Answer: A. The Finkelstein reaction is used to exchange a halide for iodine using dry acetone. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

25. What is the reagent used to prepare alkyl fluorides from alkyl chlorides or bromides?A. NaIB. Hg₂F₂C. SOCl₂D. ZnCl₂[Answer: B. Alkyl fluorides are prepared by heating alkyl chlorides or bromides with metallic fluoride, such as Hg₂F₂. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

26. What is the name of the reaction used to synthesize alkyl fluorides?A. Finkelstein reactionB. Wurtz reactionC. Swarts reactionD. Friedel-Crafts reaction[Answer: C. The Swarts reaction is used to synthesize alkyl fluorides. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Preparation of Haloarenes (MCQ 27 to 29)

27. Which method is commonly used to prepare aryl halides from aromatic amines?A. Sandmeyer’s reactionB. Finkelstein reactionC. Swarts reactionD. Free radical halogenation[Answer: A. Sandmeyer’s reaction is commonly used to prepare aryl halides from aromatic amines. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

28. Which type of reaction is used to prepare aryl chlorides or bromides from aromatic compounds?A. Electrophilic substitutionB. Nucleophilic substitutionC. Free radical halogenationD. Elimination reaction[Answer: A. Electrophilic substitution is used to prepare aryl chlorides or bromides. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

29. What is the role of a Lewis acid in the preparation of aryl halides?A. It acts as a nucleophileB. It catalyzes the reactionC. It stabilizes the productD. It removes halogens[Answer: B. A Lewis acid catalyzes the electrophilic substitution reactions for aryl halides. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Physical Properties

Boiling and Melting Points (MCQ 30 to 32)

30. Why do alkyl halides have higher boiling points than corresponding hydrocarbons?A. Higher molecular massB. Strong dipole-dipole interactionsC. Presence of hydrogen bondsD. Weak van der Waals forces[Answer: B. Alkyl halides have higher boiling points due to stronger dipole-dipole interactions. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

31. Which alkyl halide has the lowest boiling point among the following?A. ChloromethaneB. IodomethaneC. BromomethaneD. Fluoromethane[Answer: D. Fluoromethane has the lowest boiling point due to its smaller molecular size. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

32. How does branching affect the boiling point of haloalkanes?A. Increases the boiling pointB. Decreases the boiling pointC. No effect on the boiling pointD. Increases boiling point in primary halides only[Answer: B. Branching decreases the boiling point of haloalkanes. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Solubility (MCQ 33 to 34)

33. Why are haloalkanes slightly soluble in water?A. Due to strong intermolecular forcesB. Due to weak hydrogen bondsC. Due to strong covalent bondsD. Due to formation of halide ions in water[Answer: B. Haloalkanes are slightly soluble in water because weak hydrogen bonds form between water and the haloalkane. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

34. In which type of solvents do haloalkanes dissolve more readily?A. WaterB. Organic solventsC. Acidic solventsD. Polar solvents[Answer: B. Haloalkanes dissolve more readily in organic solvents due to similar intermolecular attractions. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Density (MCQ 35)

35. Which statement is correct regarding the density of haloalkanes?A. Haloalkanes are lighter than waterB. Iodides are less dense than fluoridesC. Bromo and iodo derivatives are heavier than waterD. All halides have the same density[Answer: C. Bromo and iodo derivatives are heavier than water. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Chemical Properties

Nucleophilic Substitution Reactions (SN1 and SN2) (MCQ 36 to 46)

36. What type of reaction mechanism is followed by SN2 reactions?A. First-order reactionB. Second-order reactionC. Unimolecular reactionD. Chain reaction[Answer: B. SN2 reactions follow a second-order reaction mechanism where the rate depends on the concentration of both the nucleophile and the substrate. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

37. Which of the following best describes the stereochemical outcome of an SN2 reaction?A. Retention of configurationB. RacemizationC. Inversion of configurationD. No change in configuration[Answer: C. SN2 reactions result in inversion of configuration at the chiral center. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

38. In SN1 reactions, the rate-determining step involves the formation of which intermediate?A. CarbocationB. CarbanionC. RadicalD. Transition state[Answer: A. SN1 reactions involve the formation of a carbocation intermediate in the rate-determining step. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

39. Which of the following factors increases the rate of an SN2 reaction?A. Steric hindranceB. Strong nucleophileC. Polar protic solventD. Formation of a stable carbocation[Answer: B. A strong nucleophile increases the rate of an SN2 reaction. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

40. Which type of halide is most likely to undergo an SN1 reaction?A. Methyl halideB. Primary halideC. Secondary halideD. Tertiary halide[Answer: D. Tertiary halides undergo SN1 reactions because the tertiary carbocation is highly stabilized. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

41. In an SN2 reaction, the nucleophile attacks from which side of the molecule?A. Same side as the leaving groupB. Opposite side to the leaving groupC. Above the carbon atomD. Below the carbon atom[Answer: B. In SN2 reactions, the nucleophile attacks from the opposite side to the leaving group, causing inversion of configuration. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

42. Which of the following halides reacts fastest in an SN2 mechanism?A. CH₃IB. CH₃ClC. CH₃BrD. CH₃F[Answer: A. CH₃I reacts fastest in an SN2 mechanism because iodine is a better leaving group. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

43. In SN1 reactions, what is the role of the solvent?A. It acts as a catalystB. It stabilizes the nucleophileC. It stabilizes the carbocationD. It inhibits the leaving group[Answer: C. In SN1 reactions, polar solvents help to stabilize the carbocation intermediate. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

44. Which of the following describes the stereochemical outcome of an SN1 reaction?A. Only retention of configurationB. Only inversion of configurationC. RacemizationD. Retention and inversion in equal amounts[Answer: C. SN1 reactions result in racemization, producing both retention and inversion of configuration. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

45. Which halide would have the slowest reaction rate in an SN1 mechanism?A. Tert-butyl chlorideB. Methyl chlorideC. Isopropyl bromideD. Allyl bromide[Answer: B. Methyl chloride would have the slowest reaction rate because methyl carbocations are very unstable. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

46. What is the molecular geometry around the carbon in the transition state of an SN2 reaction?A. TetrahedralB. Trigonal planarC. Trigonal bipyramidalD. Linear[Answer: C. In an SN2 reaction, the transition state has a trigonal bipyramidal geometry. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Elimination Reactions (MCQ 47 to 50)

47. In β-elimination, what is eliminated from the substrate?A. A hydrogen atom and a halide ionB. Two hydrogen atomsC. A halogen atom and an oxygen atomD. A hydroxyl group and a hydrogen atom[Answer: A. In β-elimination, a hydrogen atom and a halide ion are eliminated from adjacent carbon atoms. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

48. What is the major product in the elimination reaction of 2-bromopentane?A. 1-PenteneB. 2-PenteneC. 3-PenteneD. Pentane[Answer: B. 2-Pentene is the major product in the elimination reaction of 2-bromopentane, according to Zaitsev’s rule. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

49. Which rule is followed to determine the major product in β-elimination reactions?A. Markovnikov’s ruleB. Zaitsev’s ruleC. Saytzeff’s ruleD. Hoffman’s rule[Answer: B. Zaitsev’s rule states that the more substituted alkene is the major product in β-elimination reactions. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

50. In which type of reaction does the base abstract a proton from the β-carbon?A. Substitution reactionB. Elimination reactionC. Addition reactionD. Hydrolysis reaction[Answer: B. In elimination reactions, the base abstracts a proton from the β-carbon, leading to the formation of an alkene. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Reactions with Metals (MCQ 51 to 55)

51. What is the product formed when an alkyl halide reacts with magnesium in dry ether?A. Alkyl lithiumB. Alkyl chlorideC. Grignard reagentD. Wurtz reagent[Answer: C. The reaction of alkyl halides with magnesium in dry ether produces a Grignard reagent (RMgX). (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

52. Which of the following metals is involved in the Wurtz reaction?A. ZincB. SodiumC. MagnesiumD. Copper[Answer: B. Sodium metal is used in the Wurtz reaction to couple two alkyl halides and form a hydrocarbon. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

53. In the Wurtz reaction, what type of product is formed?A. An alcoholB. An etherC. An alkaneD. An alkene[Answer: C. The Wurtz reaction forms an alkane by coupling two alkyl halides. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

54. What is the main limitation of the Wurtz reaction?A. Formation of multiple isomersB. Difficulty in controlling reaction rateC. Requirement for high temperatureD. Only applicable to tertiary halides[Answer: A. The Wurtz reaction often leads to the formation of multiple isomers, making it difficult to obtain pure products. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

55. Which reagent is used in the Fittig reaction to form biphenyl from aryl halides?A. SodiumB. PotassiumC. MagnesiumD. Lithium[Answer: A. Sodium is used in the Fittig reaction to couple two aryl halides and form biphenyl. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Stereochemistry of Nucleophilic Substitution Reactions

Optical Activity (MCQ 56 to 60)

56. What is the optical activity of a compound that rotates the plane of polarized light to the right?A. RacemicB. DextrorotatoryC. LaevorotatoryD. Achiral[Answer: B. A compound that rotates the plane of polarized light to the right is called dextrorotatory. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

57. Which term refers to a molecule that cannot be superimposed on its mirror image?A. AchiralB. AsymmetricC. ChiralD. Symmetric[Answer: C. A molecule that cannot be superimposed on its mirror image is considered chiral. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

58. What does the term “racemic mixture” refer to?A. A mixture with no optical activityB. A mixture with only dextrorotatory isomersC. A mixture with only laevorotatory isomersD. A mixture with equal amounts of dextrorotatory and laevorotatory isomers[Answer: D. A racemic mixture contains equal amounts of dextrorotatory and laevorotatory isomers, resulting in no net optical activity. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

59. What is the outcome when a chiral alkyl halide undergoes an SN2 reaction?A. Retention of configurationB. Inversion of configurationC. RacemizationD. Formation of an achiral product[Answer: B. An SN2 reaction leads to the inversion of configuration in a chiral alkyl halide. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

60. Which instrument is used to measure the angle of rotation caused by optically active compounds?A. PolarimeterB. SpectrometerC. RefractometerD. Colorimeter[Answer: A. A polarimeter is used to measure the angle of rotation caused by optically active compounds. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Stereochemistry of Nucleophilic Substitution Reactions

SN1 and SN2 in Chiral Compounds (MCQ 61 to 65)

61. What is the stereochemical outcome of an SN1 reaction in a chiral compound?A. Complete inversionB. Retention onlyC. RacemizationD. Complete retention[Answer: C. SN1 reactions in chiral compounds lead to racemization due to the formation of a planar carbocation intermediate. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

62. In an SN2 reaction, how does the nucleophile approach the carbon atom in a chiral compound?A. From the same side as the leaving groupB. From the opposite side of the leaving groupC. From above the carbon atomD. From below the carbon atom[Answer: B. In an SN2 reaction, the nucleophile approaches the carbon atom from the opposite side of the leaving group, causing inversion of configuration. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

63. Which type of reaction mechanism proceeds through a carbocation intermediate?A. SN1B. SN2C. Both SN1 and SN2D. Neither SN1 nor SN2[Answer: A. SN1 reactions proceed through a carbocation intermediate, while SN2 reactions do not. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

64. Which of the following statements is true regarding the transition state in an SN2 reaction?A. It involves the simultaneous formation and breaking of bondsB. It involves a carbocation intermediateC. It leads to racemizationD. It involves the retention of configuration[Answer: A. In an SN2 reaction, the transition state involves the simultaneous formation of the new bond and breaking of the old bond. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

65. What is the configuration of the product formed in an SN2 reaction of a chiral alkyl halide?A. Retention of the original configurationB. Racemic mixtureC. Inversion of configurationD. No stereochemical change[Answer: C. The SN2 reaction of a chiral alkyl halide leads to the inversion of configuration. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Reactions of Haloarenes

Nucleophilic Substitution in Haloarenes (MCQ 66 to 70)

66. Why are haloarenes less reactive towards nucleophilic substitution reactions compared to haloalkanes?A. Resonance stabilizationB. Higher electronegativity of carbonC. Stronger ionic bondsD. Lack of a nucleophile[Answer: A. Haloarenes are less reactive towards nucleophilic substitution due to resonance stabilization, which gives the C-X bond partial double bond character. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

67. Which effect makes the C-X bond in haloarenes stronger and less reactive?A. Inductive effectB. Resonance effectC. HyperconjugationD. Electrophilic effect[Answer: B. The resonance effect in haloarenes strengthens the C-X bond by giving it partial double bond character. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

68. What type of mechanism is most common in nucleophilic substitution reactions of haloarenes?A. SN1B. SN2C. Electrophilic substitutionD. None of the above[Answer: D. Haloarenes generally do not undergo nucleophilic substitution by SN1 or SN2 mechanisms due to resonance stabilization. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

69. What group can enhance the reactivity of haloarenes toward nucleophilic substitution?A. Electron-donating groupB. Electron-withdrawing groupC. Alkyl groupD. None of the above[Answer: B. An electron-withdrawing group like -NO₂ enhances the reactivity of haloarenes towards nucleophilic substitution. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

70. Which position in a haloarene is most reactive towards nucleophilic substitution when an electron-withdrawing group is present?A. Ortho and para positionsB. Meta positionC. Only para positionD. Only meta position[Answer: A. The ortho and para positions become more reactive towards nucleophilic substitution when an electron-withdrawing group is present. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Electrophilic Substitution Reactions (MCQ 71 to 80)

71. Which of the following reactions occurs at the ortho and para positions in haloarenes?A. Nucleophilic substitutionB. Electrophilic substitutionC. Free radical substitutionD. Elimination reaction[Answer: B. Electrophilic substitution occurs at the ortho and para positions in haloarenes. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

72. Why is the halogen atom in haloarenes ortho-para directing in electrophilic substitution reactions?A. Due to the inductive effectB. Due to the resonance effectC. Due to the steric effectD. Due to hyperconjugation[Answer: B. The resonance effect makes the halogen atom ortho-para directing in electrophilic substitution reactions. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

73. Which reaction type is common in haloarenes?A. HalogenationB. NitrationC. SulfonationD. All of the above[Answer: D. Haloarenes undergo electrophilic substitution reactions like halogenation, nitration, and sulfonation. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

74. Which catalyst is used in the Friedel-Crafts alkylation of haloarenes?A. ZnCl₂B. AlCl₃C. H₂SO₄D. FeCl₃[Answer: B. AlCl₃ is used as a catalyst in the Friedel-Crafts alkylation of haloarenes. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

75. What happens when chlorobenzene reacts with nitric acid in the presence of sulfuric acid?A. Nitrobenzene is formedB. Chloronitrobenzene is formedC. Chlorobenzene is reducedD. No reaction[Answer: B. Chloronitrobenzene is formed when chlorobenzene reacts with nitric acid and sulfuric acid. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

76. Which of the following is an example of an electrophilic substitution reaction?A. Bromination of chlorobenzeneB. Free radical chlorination of methaneC. Halogenation of alkanesD. SN2 reaction of alkyl halides[Answer: A. Bromination of chlorobenzene is an electrophilic substitution reaction. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

77. In the sulfonation of chlorobenzene, which product is mainly formed?A. Ortho-chlorobenzenesulfonic acidB. Para-chlorobenzenesulfonic acidC. Meta-chlorobenzenesulfonic acidD. Benzenesulfonic acid[Answer: B. Para-chlorobenzenesulfonic acid is the main product formed in the sulfonation of chlorobenzene. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

78. What is the effect of chlorine in chlorobenzene on the reactivity of the benzene ring?A. Deactivating effectB. Activating effectC. No effectD. Unpredictable effect[Answer: A. Chlorine has a deactivating effect on the reactivity of the benzene ring. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

79. Which group directs electrophilic substitution to the ortho and para positions in halobenzenes?A. Halogen groupB. Alkyl groupC. Amino groupD. Nitro group[Answer: A. The halogen group in halobenzenes directs electrophilic substitution to the ortho and para positions. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

80. What is the effect of an electron-withdrawing group at the para position on electrophilic substitution in haloarenes?A. Increases reactivityB. Decreases reactivityC. No effectD. Completely stops the reaction[Answer: B. An electron-withdrawing group at the para position decreases the reactivity in electrophilic substitution. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Environmental Impact of Organohalogen Compounds

Persistence of Halogenated Compounds (MCQ 81 to 83)

81. Why are organohalogen compounds persistent in the environment?A. They are biodegradableB. They are resistant to breakdownC. They are water-solubleD. They rapidly oxidize[Answer: B. Organohalogen compounds are persistent in the environment because they are resistant to breakdown. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

82. Which of the following contributes to ozone depletion?A. FreonsB. IodoformC. MethaneD. Water vapor[Answer: A. Freons contribute to ozone depletion when released into the atmosphere. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

83. What is a major environmental concern with the use of polyhalogen compounds?A. Water pollutionB. Ozone layer depletionC. Soil degradationD. Acid rain[Answer: B. Ozone layer depletion is a major concern with the use of polyhalogen compounds like freons. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Toxicity (MCQ 84 to 85)

84. Which organohalogen compound is known to be toxic to the human nervous system?A. DichloromethaneB. ChloroformC. IodoformD. Carbon tetrachloride[Answer: A. Dichloromethane is known to be toxic to the human nervous system. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

85. What is a harmful byproduct of chloroform exposure in the presence of light?A. FreonB. PhosgeneC. OzoneD. Nitrogen dioxide[Answer: B. Phosgene is a harmful byproduct of chloroform exposure in the presence of light. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Important Polyhalogen Compounds

Dichloromethane (Methylene Chloride) (MCQ 86 to 87)

86. What is a common industrial use of dichloromethane?A. As a refrigerantB. As a solventC. As an insecticideD. As an anesthetic[Answer: B. Dichloromethane is commonly used as a solvent in industrial applications. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

87. What is a health hazard associated with prolonged exposure to dichloromethane?A. Liver damageB. Skin cancerC. Central nervous system damageD. Eye damage[Answer: C. Prolonged exposure to dichloromethane can cause central nervous system damage. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Trichloromethane (Chloroform) (MCQ 88 to 89)

88. What was chloroform primarily used for in the past?A. As a solventB. As an anestheticC. As a refrigerantD. As a pesticide[Answer: B. Chloroform was primarily used as an anesthetic in the past. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

89. What toxic substance is formed when chloroform is exposed to air and light?A. PhosgeneB. Carbon monoxideC. OzoneD. Nitric oxide[Answer: A. Phosgene is formed when chloroform is exposed to air and light. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Iodoform and Tetrachloromethane (MCQ 90 to 91)

90. Which polyhalogen compound was once used as an antiseptic?A. DichloromethaneB. IodoformC. TrichloromethaneD. Carbon tetrachloride[Answer: B. Iodoform was once used as an antiseptic. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

91. What is a major health risk associated with carbon tetrachloride exposure?A. Kidney damageB. Liver damageC. Lung diseaseD. Eye irritation[Answer: B. Carbon tetrachloride exposure is associated with liver damage. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Freons (MCQ 92 to 93)

92. Which of the following is a common use for freons?A. RefrigerationB. As a solventC. As an insecticideD. As an anesthetic[Answer: A. Freons are commonly used in refrigeration systems. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

93. What environmental concern is associated with freon usage?A. Soil degradationB. Water pollutionC. Ozone layer depletionD. Greenhouse gas emissions[Answer: C. Freons are associated with ozone layer depletion. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

DDT (MCQ 94 to 95)

94. Which compound was used as an insecticide and later banned due to environmental concerns?A. DichloromethaneB. ChloroformC. DDTD. Freon[Answer: C. DDT was used as an insecticide and later banned due to its environmental impact. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

95. What is a major ecological concern with DDT?A. It contaminates soilB. It accumulates in the food chainC. It evaporates easilyD. It degrades ozone[Answer: B. DDT accumulates in the food chain, leading to long-term ecological damage. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Exercises and Problems

Structural and Nomenclature Problems (MCQ 96 to 98)

96. What is the IUPAC name for CH₃CH₂CH₂Br?A. Propyl bromideB. BromopropaneC. Butyl bromideD. Ethyl bromide[Answer: B. The IUPAC name for CH₃CH₂CH₂Br is bromopropane. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

97. What is the structure of 2-chloropropane?A. CH₃CH₂ClB. CH₃CHClCH₃C. CH₃CCl₃D. CCl₄[Answer: B. The structure of 2-chloropropane is CH₃CHClCH₃. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

98. What is the common name of CHCl₃?A. Methylene chlorideB. ChloroformC. Carbon tetrachlorideD. Dichloromethane[Answer: B. CHCl₃ is commonly known as chloroform. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Reaction Mechanisms (MCQ 99)

99. What is the major product of the reaction of propene with HCl according to Markovnikov’s rule?A. 1-ChloropropaneB. 2-ChloropropaneC. PropaneD. Propyl chloride[Answer: B. 2-Chloropropane is the major product of the reaction of propene with HCl according to Markovnikov’s rule. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Applications and Case Studies (MCQ 100)

100. Which of the following is an application of the Finkelstein reaction?A. Formation of alkyl fluoridesB. Halogen exchange to form alkyl iodidesC. Formation of Grignard reagentsD. Dehydrohalogenation[Answer: B. The Finkelstein reaction is used for halogen exchange to form alkyl iodides. (Haloalkanes and Haloarenes MCQ by Top100MCQ.com) ]   

Most Asked Questions: Haloalkanes and Haloarenes

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