NCERT BOOK CLASS 12TH CHEMISTRY MCQ
Chapter 6 : Haloalkanes and Haloarenes
Important MCQs with Answers
1. What are Haloalkanes?
a) Hydrocarbons in which hydrogen atoms are replaced by halogens
b) Hydrocarbons containing only carbon and hydrogen
c) Hydrocarbons containing oxygen atoms
d) None of the above
Answer: a) Hydrocarbons in which hydrogen atoms are replaced by halogens
2. What is the common name of Chloromethane?
a) Methyl chloride
b) Ethyl chloride
c) Propyl chloride
d) Butyl chloride
Answer: a) Methyl chloride
3. Which of the following is not a Haloalkane?
a) CH₃Cl
b) C₂H₅Br
c) C₆H₅Cl
d) CH₂Cl₂
Answer: c) C₆H₅Cl (This is a Haloarene)
4. According to IUPAC rules, which prefix is used in the nomenclature of Haloalkanes?
a) -ol
b) -aldehyde
c) -halo
d) -oxo
Answer: c) -halo
5. What is the IUPAC name of Chloroform?
a) Trichloromethane
b) Dichloromethane
c) Methyl chloride
d) Tetrachloromethane
Answer: a) Trichloromethane
6. Which of the following is an Alkyl halide?
a) C₆H₅Br
b) CH₃CH₂Br
c) CH₂=CHCl
d) C₆H₅CH₂Cl
Answer: b) CH₃CH₂Br
7. What is the general use of Haloalkanes?
a) As solvents
b) As fuels
c) In food items
d) None of the above
Answer: a) As solvents
8. What is the nature of the Carbon-Halogen bond?
a) Ionic
b) Polar covalent
c) Non-polar covalent
d) Metallic
Answer: b) Polar covalent
9. Which of the following is a primary alkyl halide?
a) (CH₃)₂CHBr
b) CH₃CH₂CH₂Br
c) (CH₃)₃CBr
d) C₆H₅Br
Answer: b) CH₃CH₂CH₂Br
10. From which side does the nucleophile attack in an SN² reaction?
a) From the backside of carbon
b) From the front side of carbon
c) From the backside of halogen
d) From the front side of halogen
Answer: b) From the front side of carbon
11. How many steps are involved in an SN¹ reaction?
a) 1
b) 2
c) 3
d) 4
Answer: b) 2
12. In which reaction does racemization occur?
a) SN²
b) SN¹
c) E²
d) E¹
Answer: b) SN¹
13. How does the rate of SN¹ reaction change with increasing solvent polarity?
a) Increases
b) Decreases
c) Remains unchanged
d) First increases then decreases
Answer: a) Increases
14. Which of the following is a nucleophile?
a) OH⁻
b) H⁺
c) BF₃
d) AlCl₃
Answer: a) OH⁻
15. What is used in the Friedel-Crafts reaction?
a) Alkyl halide
b) Alcohol
c) Aldehyde
d) Ketone
Answer: a) Alkyl halide
16. How is the chlorine atom bonded to carbon in Chlorobenzene?
a) Ionic bond
b) Covalent bond
c) Metallic bond
d) Hydrogen bond
Answer: b) Covalent bond
17. Why is the halogen atom in Haloarenes inactive?
a) +I effect (Inductive effect)
b) -I effect
c) +R effect (Resonance effect)
d) -R effect
Answer: c) +R effect (Resonance effect)
18. What is the abbreviation for Dichlorodiphenyltrichloroethane?
a) DDT
b) BHC
c) PVC
d) TNT
Answer: a) DDT
19. Which of the following is a pesticide?
a) Chloroform
b) Dichloromethane
c) Benzene hexachloride
d) Carbon tetrachloride
Answer: c) Benzene hexachloride
20. What is obtained by the hydrolysis of Haloalkanes?
a) Alcohol
b) Alkene
c) Alkyne
d) Alkane
Answer: a) Alcohol
21. What is the general formula of a Grignard reagent?
a) R-Mg-X
b) R-X
c) R-OH
d) R-COOH
Answer: a) R-Mg-X
22. Which metal is used in the preparation of Grignard reagent?
a) Sodium
b) Magnesium
c) Iron
d) Copper
Answer: b) Magnesium
23. What is Carbon tetrachloride used for?
a) Fire extinguisher
b) Fuel
c) Food preservative
d) Medicine
Answer: a) Fire extinguisher
24. Which compound is harmful to the ozone layer?
a) CH₄
b) CFCs
c) CO₂
d) H₂O
Answer: b) CFCs
25. What were Chlorofluorocarbons (CFCs) used for?
a) Refrigerants
b) Fuels
c) Explosives
d) Fertilizers
Answer: a) Refrigerants
26. What is the correct order of reactivity of Haloalkanes?
a) RI > RBr > RCl > RF
b) RF > RCl > RBr > RI
c) RCl > RBr > RI > RF
d) RBr > RI > RCl > RF
Answer: a) RI > RBr > RCl > RF
27. Which compound is the most reactive?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
28. What is formed in Williamson synthesis?
a) Ether
b) Alcohol
c) Alkene
d) Alkyne
Answer: a) Ether
29. Which compound is the least reactive?
a) CH₃CH₂Cl
b) (CH₃)₂CHCl
c) (CH₃)₃CCl
d) C₆H₅Cl
Answer: d) C₆H₅Cl
30. What is obtained by the reduction of Haloalkanes?
a) Alkane
b) Alkene
c) Alkyne
d) Alcohol
Answer: a) Alkane
31. Which of the following is not a Haloalkane?
a) CH₃Br
b) C₂H₅I
c) C₆H₅Cl
d) CH₂Cl₂
Answer: c) C₆H₅Cl
32. In Haloalkanes, which Carbon-Halogen bond has the longest length?
a) C-F
b) C-Cl
c) C-Br
d) C-I
Answer: d) C-I
33. Which compound is the most polar?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
34. In an SN² reaction, the reaction rate depends on:
a) Only the concentration of alkyl halide
b) Only the concentration of nucleophile
c) Both the concentration of alkyl halide and nucleophile
d) None of the above
Answer: c) Both the concentration of alkyl halide and nucleophile
35. Which of the following is the best nucleophile?
a) F⁻
b) Cl⁻
c) Br⁻
d) I⁻
Answer: d) I⁻
36. What type of effect does the halogen atom show in Haloarenes?
a) Electron-releasing
b) Electron-withdrawing
c) No effect
d) None of the above
Answer: b) Electron-withdrawing
37. Which catalyst is used in Friedel-Crafts reaction?
a) Ni
b) FeCl₃
c) Pt
d) Pd
Answer: b) FeCl₃
38. Which compound has the lowest boiling point?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
39. What is obtained when Haloalkanes react with aqueous KOH?
a) Alcohol
b) Alkene
c) Alkyne
d) Alkane
Answer: a) Alcohol
40. What is formed when Haloalkanes react with alcoholic KOH?
a) Alcohol
b) Alkene
c) Alkyne
d) Alkane
Answer: b) Alkene
41. Which compound has the highest boiling point?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
42. In which industrial process are Haloalkanes used?
a) Plastic manufacturing
b) Metal extraction
c) Paper manufacturing
d) Textile industry
Answer: a) Plastic manufacturing
43. Which compound is the least polar?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
44. Which of the following is not a method for the preparation of Haloalkanes?
a) Halogenation of alkanes
b) Reaction of alcohol with halogen acid (HX)
c) Hydrogenation of alkene
d) Use of silver halide
Answer: c) Hydrogenation of alkene
45. What is the solubility of Haloalkanes in water?
a) Highly soluble
b) Less soluble
c) Insoluble
d) None of the above
Answer: b) Less soluble
46. Which of the following is the most reactive Haloarene?
a) Fluorobenzene
b) Chlorobenzene
c) Bromobenzene
d) Iodobenzene
Answer: d) Iodobenzene
47. What is the general formula of Haloalkanes?
a) CnH₂n+1X
b) CnH₂nX
c) CnH₂n-1X
d) CnH₂n+2X
Answer: a) CnH₂n+1X
48. Which compound cannot form a Grignard reagent?
a) CH₃Cl
b) C₂H₅Br
c) C₆H₅Cl
d) (CH₃)₃CCl
Answer: d) (CH₃)₃CCl
49. In which medical procedure are Haloalkanes used?
a) Anesthesia
b) Antibiotics
c) Vaccines
d) None of the above
Answer: a) Anesthesia
50. Which of the following is the least reactive Haloalkane?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
51. Which of the following compounds is a secondary alkyl halide?
a) CH₃CH₂CH₂Br
b) (CH₃)₂CHBr
c) (CH₃)₃CBr
d) CH₃Br
Answer: b) (CH₃)₂CHBr
52. In which reaction does bond cleavage and new bond formation occur simultaneously?
a) SN¹
b) SN²
c) E¹
d) E²
Answer: b) SN²
53. Which of the following compounds is the slowest in nucleophilic substitution reactions?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
54. What type of compound is used in Williamson synthesis?
a) Alcohol and sodium halide
b) Alcohol and sodium alkoxide
c) Alkyl halide and sodium alkoxide
d) Alkene and hydrogen halide
Answer: c) Alkyl halide and sodium alkoxide
55. Which of the following is the best reducing agent?
a) LiAlH₄
b) NaBH₄
c) Zn/HCl
d) Sn/HCl
Answer: a) LiAlH₄
56. In what is Chloroform stored when kept in the presence of air and light?
a) Water
b) Ethyl alcohol
c) Carbon disulfide
d) Acetone
Answer: b) Ethyl alcohol
57. Which of the following compounds cannot react with Grignard reagent?
a) CH₃OH
b) H₂O
c) CO₂
d) CH₃CH₂Br
Answer: b) H₂O
58. What is obtained when Haloalkanes are boiled with aqueous KOH?
a) Alkene
b) Alcohol
c) Ether
d) Aldehyde
Answer: b) Alcohol
59. Which of the following compounds is the most volatile?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
60. What type of catalyst is used in Friedel-Crafts alkylation?
a) Acidic catalyst
b) Basic catalyst
c) Neutral catalyst
d) Metallic catalyst
Answer: a) Acidic catalyst
61. Which of the following compounds has the least polar C-X bond?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
62. What type of effect does the halogen atom show in Haloarenes?
a) +I effect
b) -I effect
c) +M effect
d) -M effect
Answer: b) -I effect
63. Which of the following compounds is the most reactive?
a) CH₃CH₂CH₂Br
b) (CH₃)₂CHBr
c) (CH₃)₃CBr
d) C₆H₅Br
Answer: a) CH₃CH₂CH₂Br
64. What is formed as an intermediate in SN¹ reaction?
a) Carbocation
b) Carbanion
c) Free radical
d) Compound radical
Answer: a) Carbocation
65. Which of the following compounds has the highest boiling point?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
66. What is Carbon tetrachloride used for?
a) Fire extinguisher
b) Solvent
c) Pesticide
d) All of the above
Answer: d) All of the above
67. Which of the following compounds is the most toxic?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
68. Why is the solubility of Haloalkanes in water low?
a) High polarity
b) Lack of hydrogen bonding
c) High molecular weight
d) All of the above
Answer: b) Lack of hydrogen bonding
69. Which of the following compounds is the least reactive?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
70. In which industrial processes are Haloalkanes used?
a) Plastic manufacturing
b) Rubber industry
c) Pharmaceutical manufacturing
d) All of the above
Answer: d) All of the above
71. Which of the following compounds is the most volatile?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: a) CH₃F
72. What is obtained when Haloalkanes are boiled with aqueous KOH?
a) Alkene
b) Alcohol
c) Ether
d) Aldehyde
Answer: b) Alcohol
73. Which of the following compounds is the most reactive?
a) CH₃CH₂CH₂Br
b) (CH₃)₂CHBr
c) (CH₃)₃CBr
d) C₆H₅Br
Answer: a) CH₃CH₂CH₂Br
74. What is formed as an intermediate in SN¹ reaction?
a) Carbocation
b) Carbanion
c) Free radical
d) Compound radical
Answer: a) Carbocation
75. Which of the following compounds has the highest boiling point?
a) CH₃F
b) CH₃Cl
c) CH₃Br
d) CH₃I
Answer: d) CH₃I
76. Williamson Synthesis is used for the preparation of?
a) Alcohol
b) Ether
c) Alkene
d) Aldehyde
Answer: b) Ether
77. What happens in Finkelstein Reaction?
a) Conversion of alkyl chloride to alkyl iodide
b) Conversion of alcohol to ether
c) Conversion of alkene to alkane
d) Conversion of aldehyde to ketone
Answer: a) Conversion of alkyl chloride to alkyl iodide
78. Which catalyst is used in Swarts Reaction?
a) FeCl₃
b) AgF
c) AlCl₃
d) ZnCl₂
Answer: b) AgF
79. What is used in Grignard Reaction?
a) R-Mg-X
b) R-Li
c) R-Zn-X
d) R-Al-X
Answer: a) R-Mg-X
80. What is used in Friedel-Crafts Alkylation?
a) Alkyl halide + AlCl₃
b) Alcohol + H₂SO₄
c) Alkene + HCl
d) Alkyne + NH₃
Answer: a) Alkyl halide + AlCl₃
81. What is obtained in Wurtz Reaction?
a) Higher alkane
b) Alkene
c) Alkyne
d) Cycloalkane
Answer: a) Higher alkane
82. Reimer-Tiemann Reaction is used for preparation of?
a) Salicylaldehyde from phenol
b) Toluene from benzene
c) Alkane from alkene
d) Ether from alcohol
Answer: a) Salicylaldehyde from phenol
83. What happens in Sandmeyer Reaction?
a) Aromatic amine to aromatic halide
b) Alcohol to ether
c) Aldehyde to carboxylic acid
d) Ketone to alcohol
Answer: a) Aromatic amine to aromatic halide
84. Balz-Schiemann Reaction is used for preparation of?
a) Aromatic fluoride
b) Aromatic chloride
c) Aromatic bromide
d) Aromatic iodide
Answer: a) Aromatic fluoride
85. Which solvent is used in Finkelstein Reaction?
a) Water
b) Acetone
c) Ethanol
d) Methanol
Answer: b) Acetone