Haloalkanes and Haloarenes Mock Test – Class 12 Chemistry

1. The principal organic product formed when -methylpropan--ol reacts with thionyl chloride is:

2. The principal product obtained by adding to -methylpropene is:

3. A learner predicts that chlorobenzene will rapidly give iodobenzene with in dry acetone. The prediction is unsuitable mainly because:

4. The compound is named:

5. A laboratory record compares solvolysis of tert-butyl fluoride and tert-butyl iodide in the same polar protic solvent. Tert-butyl iodide reacts much faster. The best explanation is:

6. During a reaction, one species donates an electron pair to an electron-deficient carbon centre. The roles of the two participants are:

7. The carbon atom of cyanide ion is isotopically labelled in . When this reagent reacts with bromoethane, which product correctly shows the position of the label?

8. The ideal rate law for an reaction between a haloalkane and a nucleophile is:

9. An elimination experiment gives the following alkene composition from a single haloalkane:

The best interpretation is:

10. Read the following statements about the IUPAC naming of polyhalo compounds.
Statement I: Every halogen atom is assigned a locant.
Statement II: Prefixes such as di and tri are ignored when arranging unlike substituents alphabetically.
Statement III: Numbering is selected only after the substituent prefixes have been alphabetised.

11. In a reaction-coordinate diagram, the vertical and horizontal axes usually represent, respectively:

12. -Chloro--dinitrobenzene is treated with hydroxide and the product mixture is acidified. The expected organic product is:

13. Evaluate the following conversions of bromoethane.

The appropriate evaluation is:

14. Appraise the following statements about allylic halides.
Statement I: The halogen-bearing carbon is -hybridised.
Statement II: The halogen-bearing carbon is adjacent to a carbon–carbon double bond.
Statement III: The halogen must be bonded directly to one of the double-bonded carbons.

15. -Bromo--methylbutane, , undergoes hydrolysis through an pathway. A hydride shift produces a more stable carbocation before water attacks. The major rearranged alcohol is:

16. The general equation that best represents nucleophilic substitution of a haloalkane is:

17. The structure that represents an allylic halide is:

18. A chiral haloalkane is drawn with its carbon–bromine bond on a solid wedge pointing toward the observer. Under an ideal backside attack and with the same viewing direction, the new carbon–nucleophile bond is most reasonably drawn:

19. A carbon atom is bonded to one other carbon atom and three hydrogen atoms. On the basis of its carbon attachments, it is a:

20. The common and IUPAC names of are, respectively:

21. A haloalkane is best described as a compound in which:

22. Assertion: Addition of across the double bond of ethene produces a vicinal dibromide.
Reason: One bromine atom becomes attached to each of the two carbon atoms that originally formed the double bond.

23. The principal organic product formed when -methylpropan--ol reacts with is:

24. Use the arrangements described below.

P.
Q.

Which description is correct?

25. Combination of two ethyl radicals during radical halogenation produces the side product:

26. Steric hindrance at four alkyl bromides is assessed for an ideal reaction.
P. — minimal hindrance
Q. — low hindrance
R. — moderate hindrance
S. — severe hindrance

Select the appropriate evaluation.

27. Assertion: Predatory birds may receive high DDT exposure even when the concentration of DDT in surrounding water is very low.
Reason: Persistent DDT can become progressively concentrated through an aquatic food chain.

28. tert-Butyl alcohol gives rapid turbidity when treated with Lucas reagent because:

29. Which equation correctly represents the formation of a Grignard reagent from an alkyl halide?

30. Two hypothetical energy barriers are considered for chlorobenzene.

Path P: carbon–chlorine ionisation followed by nucleophile capture
Path Q: concerted backside nucleophile attack

Both pathways have very high barriers under ordinary conditions. Which explanation correctly assigns the main difficulty?

31. An alkyl-substituted chlorobenzene is subjected to three separate treatments.

Case P: and ultraviolet light
Case Q:
Case R: hot strong oxidising agent followed by acidification

Which mapping is correct?

32. A four-carbon chain is written as . Its IUPAC name is:

33. Match each locant pair in Column I with its positional descriptor in Column II.

34. Beta-elimination rather than nucleophilic substitution is expected to dominate for:

35. Assertion: Thionyl chloride is commonly preferred over many phosphorus chlorides for preparing a pure alkyl chloride.
Reason: The and produced during the reaction can leave the mixture as gases.

36. Assertion: Carbon tetrachloride has zero molecular dipole moment.
Reason: Its four identical carbon–chlorine bond dipoles are arranged symmetrically and cancel vectorially.

37. The substrate expected to undergo the Finkelstein reaction most readily is:

38. Assertion: Reduction of a monohaloalkane normally preserves the number of carbon atoms in its organic skeleton.
Reason: The transformation replaces the halogen atom by hydrogen rather than coupling two carbon groups.

39. A very strong nucleophile is added to an ideal reaction mixture, but the haloalkane concentration and temperature are unchanged. Which statement is most accurate?

40. Among the three dichlorobenzene isomers, -dichlorobenzene often has a higher melting point than the ortho and meta isomers mainly because:

41. The following table compares proposed features of an reaction.

The appropriate evaluation is:

42. The compound that contains a stereogenic carbon atom is:

43. A learner numbers from the left and obtains -chlorobutane. The required correction is:

44. Use the graph description below. A reaction-coordinate diagram has reactants and products separated by a single energy maximum, with no minimum between them. This profile is most consistent with:

45. A tertiary haloalkane is dissolved in water and slowly forms an alcohol without addition of a strong nucleophile. The observation is most consistent with:

46. Neopentyl chloride, , is classified as a primary haloalkane because:

47. Study the two reactions below.

The appropriate evaluation is:

48. Potassium nitrite and silver nitrite can give different products with the same haloalkane because the nitrite ion is:

49. In the balanced reaction below, the missing coefficient before is ______.

50. The primary, secondary, or tertiary classification of a monohaloalkane is determined by: