MCQs – Haloalkanes & Haloarenes Class 12

MCQs – Haloalkanes & Haloarenes

1. The general formula of alkyl halide is:
a) CnH₂n+₂X
b) CnH₂n+1X
c) CnH₂n–1X
d) CnH₂nX

2. Which of the following alkyl halides undergoes SN1 reaction most readily?
a) CH₃Cl
b) CH₃CH₂Cl
c) (CH₃)₃CCl
d) CH₃CH₂CH₂Cl

3. Which of the following is most reactive towards nucleophilic substitution?
a) Benzyl chloride
b) Vinyl chloride
c) Aryl chloride
d) Chlorobenzene

4. Which of the following haloalkanes is most reactive towards β–elimination?
a) 1-chlorobutane
b) 2-chlorobutane
c) 2-chloro-2-methylpropane
d) Chloromethane

5. The C–X bond strength in haloalkanes decreases in the order:
a) C–I > C–Br > C–Cl > C–F
b) C–F > C–Cl > C–Br > C–I
c) C–Cl > C–F > C–Br > C–I
d) C–Br > C–Cl > C–F > C–I

6. The Wurtz reaction is used to prepare:
a) Alkanes
b) Alkenes
c) Alcohols
d) Ethers

7. Chlorobenzene is less reactive towards nucleophilic substitution due to:
a) Resonance
b) High bond dissociation energy of C–Cl
c) Partial double bond character of C–Cl bond
d) All of these

8. Which of the following is used as a refrigerant (Freon)?
a) CCl₄
b) CF₂Cl₂
c) CHCl₃
d) CH₂Cl₂

9. Which of the following is called “methylating agent”?
a) CH₃I
b) CH₃Cl
c) CH₃Br
d) CH₃F

10. Iodoform test is given by:
a) CH₃CH₂Cl
b) CH₃Cl
c) CH₃CH(OH)CH₃
d) CH₃CH₂I

11. Chloroform on oxidation with air and light gives a poisonous gas:
a) COCl₂
b) HCl
c) Cl₂
d) CHCl₃O

12. Which of the following is used as an anaesthetic?
a) CCl₄
b) CHCl₃
c) CF₂Cl₂
d) C₂H₅Cl

13. Which one is used as a solvent in dry cleaning?
a) CHCl₃
b) CCl₄
c) C₂H₅Cl
d) CH₂Cl₂

14. Which of the following shows +I effect most strongly?
a) –Cl
b) –Br
c) –I
d) –F

15. When chlorobenzene is treated with NaOH at 623 K and 300 atm, the product is:
a) Benzyl alcohol
b) Phenol
c) Benzaldehyde
d) Aniline

16. Which of the following will form Grignard reagent?
a) C₆H₆
b) CH₄
c) C₂H₅Cl
d) C₂H₅OH

17. Allyl chloride is more reactive than n-propyl chloride in nucleophilic substitution because:
a) Inductive effect
b) Hyperconjugation
c) Resonance stabilization of carbocation
d) None of these

18. Freons cause:
a) Acid rain
b) Ozone layer depletion
c) Greenhouse effect
d) Photochemical smog

19. Aryl halides are less reactive towards nucleophilic substitution than alkyl halides due to:
a) Resonance effect
b) Partial double bond character
c) Steric hindrance
d) All of the above

20. The reaction of chlorobenzene with Cl₂/FeCl₃ gives:
a) Benzyl chloride
b) Dichlorobenzene
c) Benzyl alcohol
d) Chlorotoluene

✅ Answer Key

  1. b
  2. c
  3. a
  4. c
  5. b
  6. a
  7. d
  8. b
  9. a
  10. c
  11. a
  12. b
  13. b
  14. b
  15. b
  16. c
  17. c
  18. b
  19. d
  20. b

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