SaitechAI – Haloalkanes & Haloarenes

Class 12 CBSE • 100 Frequently Asked 1-Mark Questions (No Answers)

1-Mark Test • PYQ Style
  1. Write the IUPAC name of CH₃–CH₂–CH₂–Cl.
  2. Write the IUPAC name of CH₃–CH(Br)–CH₃.
  3. Write the IUPAC name of C₆H₅–Cl.
  4. What is the common name of CH₃–CH₂–Br?
  5. Give the general formula of a mono-haloalkane.
  6. What is meant by a primary (1°) haloalkane?
  7. What is meant by a tertiary (3°) haloalkane?
  8. Give one example of a secondary (2°) haloalkane.
  9. What is meant by the term “haloarene”?
  10. Give one example of a mono-haloarene other than chlorobenzene.
  11. Why are haloalkanes usually polar molecules?
  12. Which C–X bond is more polar: C–F or C–I?
  13. Arrange CH₃Cl, CH₃Br, CH₃I in increasing order of bond strength of C–X bond.
  14. Why do haloalkanes have higher boiling point than alkanes of comparable molecular mass?
  15. Which will have higher boiling point: CH₃Cl or CH₃Br (for same number of carbon atoms)?
  16. Why do boiling points of haloalkanes increase with increase in halogen atomic mass in a homologous series?
  17. Why are haloalkanes generally insoluble in water?
  18. State the trend of density in haloalkanes with increase in halogen atomic mass.
  19. Which is more reactive towards nucleophilic substitution: CH₃Cl or CCl₄?
  20. Why is CCl₄ a non-polar molecule though C–Cl bond is polar?
  21. Write the general formula of Grignard reagents.
  22. Name the reaction used for the preparation of higher alkanes from haloalkanes using sodium metal.
  23. Write the balanced equation for the preparation of ethane from chloroethane using sodium.
  24. Which reagents are used in the Swarts reaction?
  25. Name the reaction used to convert alkyl chlorides to alkyl fluorides using metallic fluorides.
  26. Give one method for the preparation of chloroethane from ethanol.
  27. Name the reagent used to convert an alcohol to haloalkane in the presence of ZnCl₂.
  28. Which halogen acid (HX) is most reactive towards alcohol in Lucas test?
  29. What is the order of reactivity of HX (HF, HCl, HBr, HI) for formation of haloalkanes from alcohols?
  30. Name the reagent: PCl₅ used for converting alcohols to haloalkanes.
  31. What is nucleophilic substitution reaction?
  32. What is meant by SN1 reaction?
  33. What is meant by SN2 reaction?
  34. Which type of haloalkane (1°, 2°, 3°) generally prefers SN1 mechanism?
  35. Which type of haloalkane (1°, 2°, 3°) generally prefers SN2 mechanism?
  36. State the order of reactivity of primary, secondary and tertiary alkyl halides towards SN2 reaction.
  37. State the order of reactivity of primary, secondary and tertiary alkyl halides towards SN1 reaction.
  38. What is meant by a nucleophile? Give one example.
  39. What is meant by a leaving group? Give one example in haloalkanes.
  40. Why are iodides more reactive than chlorides towards nucleophilic substitution?
  41. What is β-elimination reaction?
  42. Which reagent is used for dehydrohalogenation of haloalkanes?
  43. State Saytzeff’s (Zaitsev’s) rule for elimination reactions.
  44. Name the major product obtained when 2-bromopropane is treated with alcoholic KOH.
  45. What happens when an alkyl halide is treated with aqueous KOH?
  46. What happens when an alkyl halide is treated with alcoholic KOH?
  47. What type of reaction converts an alkyl halide into an alkene?
  48. What are ambident nucleophiles? Give one example.
  49. Name the type of isomerism shown by nitro and nitrite isomers.
  50. Give the formula of a nitro isomer and its corresponding nitrite isomer (any example).
  51. What is meant by “aryl halide”?
  52. Why are aryl halides less reactive than alkyl halides towards nucleophilic substitution?
  53. Why does chlorobenzene not undergo SN1 or SN2 reactions easily?
  54. What is the effect of resonance in aryl halides on the C–Cl bond?
  55. Name the type of hybridisation of carbon in chlorobenzene.
  56. Why is the C–Cl bond length in chlorobenzene shorter than in CH₃Cl?
  57. What is the +M (resonance donating) effect?
  58. How does a –I group (like –NO₂) affect reactivity of aryl halides towards nucleophilic substitution?
  59. Which position (o, m, p) is most activated for nucleophilic substitution in nitro-substituted aryl halides?
  60. Name the reaction in which chlorobenzene is converted into phenol using NaOH at high temperature and pressure.
  61. What is the Finkelstein reaction?
  62. Which halide salt is used in Finkelstein reaction?
  63. Give one example of Finkelstein reaction (no mechanism, only equation).
  64. What is the Wurtz reaction?
  65. Why is Wurtz reaction not suitable for preparation of unsymmetrical alkanes?
  66. What is the role of dry ether in Wurtz reaction?
  67. Name the reaction used to convert aryl diazonium salts into aryl halides using CuX/HX.
  68. Write the general formula of aryl diazonium salt.
  69. Name the reagent used to convert aniline to benzene diazonium chloride.
  70. State one condition (temperature) for the stability of benzene diazonium chloride.
  71. What is chloromethane used for (give one use)?
  72. Name one polyhalogen compound used as a local anaesthetic.
  73. Write one harmful effect of carbon tetrachloride (CCl₄) on human health.
  74. Name one polyhalogen compound used as a propellant or refrigerant.
  75. Why have CFCs (chlorofluorocarbons) been largely phased out?
  76. What is the main environmental problem caused by CFCs?
  77. Name one polyhalogen compound used as an insecticide.
  78. Write the full form of DDT.
  79. Why is DDT considered environmentally harmful?
  80. What is meant by the term “persistent” with regard to pesticides?
  81. Write the structure of 1,2-dichloroethane.
  82. Write the structure of 1-bromo-2-chloroethane.
  83. Write the IUPAC name of CH₃–CH₂–CH₂–Br.
  84. Write the IUPAC name of CH₃–CH(Cl)–CH₂–CH₃.
  85. Write the structure of p-dichlorobenzene.
  86. Write the structure of m-bromotoluene.
  87. Write the structure of 2-bromobutane.
  88. Write the structure of 1-chloro-4-nitrobenzene.
  89. Write the IUPAC name of C₆H₅–CH₂–Cl.
  90. Write the IUPAC name of C₆H₅–CH(CH₃)–Br.
  91. What is meant by allylic halide? Give one example.
  92. What is meant by benzylic halide? Give one example.
  93. Which is more reactive towards SN1 reaction: benzylic halide or simple alkyl halide? (no explanation)
  94. Why are benzylic halides more reactive towards SN1 than alkyl halides? (one reason)
  95. What is meant by vinylic halide?
  96. Are vinylic halides reactive towards nucleophilic substitution? (state briefly)
  97. Give one example of a vinylic halide.
  98. What is meant by geminal dihalide?
  99. What is meant by vicinal dihalide?
  100. Give one example of a vicinal dihalide.
  101. What is the role of silver nitrate in testing the nature of C–X bond in halo compounds?
  102. How can you distinguish between 1° and 3° alkyl halides using alcoholic AgNO₃?
  103. Mention one difference in reactivity between aryl halides and alkyl halides towards Friedel–Crafts reaction.
  104. Which reagent is used as a catalyst in Friedel–Crafts alkylation of benzene using haloalkane?
  105. Name the reaction in which haloalkane reacts with sodium alkoxide to give ether.
  106. Write the equation for the reaction of bromoethane with alcoholic KCN.
  107. Write the equation for the reaction of bromoethane with alcoholic AgCN.
  108. Why does reaction with KCN give alkyl cyanide whereas reaction with AgCN gives isocyanide?
  109. State one use of freons.
  110. What is meant by the term “denatured alcohol” in context of halo compounds?
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