Haloalkanes and Haloarenes Mock Test – Class 12 Chemistry

1. Assess the following stages of chlorofluorocarbon-related ozone depletion.

The appropriate evaluation is:

2. Compared with chlorination of the same alkane, bromination is generally:

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

4. Review the proposed roles in an hydrolysis.

The appropriate evaluation is:

5. Which reagent sequence converts propene into -dibromopropane and then regenerates propene?

6. The compounds and have the same molecular formula but differ because:

7. 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.

8. A compound contains five carbon atoms, eleven hydrogen atoms, and one bromine atom. Its classification by halogen count is:

9. The claim “A halogenated compound that is stable during use is necessarily environmentally desirable” is:

10. Assertion: Propan--ol gives a positive iodoform test.
Reason: Under the reaction conditions, propan--ol can be oxidised to propanone, which contains a unit.

11. A graph plots carbon–halogen bond dissociation enthalpy on the vertical axis against bond length on the horizontal axis for , , , and . The overall relationship is expected to show:

12. The proposed first step

is highly unfavourable in an ordinary reaction mainly because:

13. The IUPAC name of is:

14. Review the following reactions of bromobenzene.

Which evaluation is appropriate?

15. Arrange the following events in the correct order for stereochemical product formation in an reaction.
P. The leaving group departs.
Q. A planar carbocation forms.
R. The nucleophile attacks from either face.
S. Products of both configurations may be obtained.

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

17. Why does an reaction of a single enantiomer not always produce an exactly mixture of the two product enantiomers?

18. Evaluate the following statements about aromatic diazonium salts.
Statement I: They are commonly prepared from primary aromatic amines.
Statement II: Their preparation is carried out at low temperature.
Statement III: Replacement of the diazonium group occurs without liberation of nitrogen gas.

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

20. The common name “methylene chloride” refers to:

21. A laboratory record gives the following condition–product assignments.

The row requiring correction is:

22. Assertion: A haloalkane must contain at least one beta hydrogen to form an alkene by ordinary dehydrohalogenation.
Reason: The beta hydrogen and the halogen are removed from adjacent carbons while a double bond forms between those carbons.

23. Raising the temperature often increases the proportion of elimination product relative to substitution product because:

24. Ethylbenzene undergoes controlled monochlorination under ultraviolet light. The favoured side-chain product is:

25. A graph plots the volume of nitrogen evolved on the vertical axis against time on the horizontal axis during a complete Sandmeyer reaction. The most reasonable curve:

26. Analyse the following energy-profile interpretations.

Which evaluation is appropriate?

27. DDT concentrations in an aquatic sample and in fish-eating bird tissue are and , respectively. On this common mass basis, the concentration in the bird tissue is greater by a factor of:

28. The ideal rate law for an reaction of a haloalkane is:

29. Judge the following statements about melting points of halo compounds.
Statement I: Crystal packing can influence melting point strongly.
Statement II: Greater molecular symmetry may improve packing and raise melting point.
Statement III: Melting point must increase smoothly with molar mass in every homologous series.

30. Analyse the carbon-count changes in the following conversions.

The appropriate evaluation is:

31. Two reactions are proposed.
Case P: with in dimethyl sulfoxide
Case Q: in aqueous ethanol

The most appropriate mechanism assignment is:

32. A substitution energy profile shows products at a lower energy than reactants, but it also shows a high transition-state maximum. The best conclusion is:

33. Which two-step sequence converts propene into propan--ol through a haloalkane intermediate?

34. A sample of -methylbutane undergoes monobromination. Ignoring stereoisomers and product proportions, the number of distinct constitutional monobromo products is:

35. If the initiation step is prevented during a proposed free-radical chlorination, the most immediate consequence is that:

36. The structure has the IUPAC name:

37. Use the graph description below. The vertical axis shows relative rate on a logarithmic scale. The horizontal axis lists benzyl bromide, bromoethane, tert-butyl bromide, and bromobenzene under the same nucleophile and solvent conditions. Which pattern is most reasonable?

38. A laboratory preparation produces of butane by Wurtz coupling of bromoethane. If sodium is used in the exact stoichiometric amount and its molar mass is , the required mass of sodium is:

39. Between chloromethane, , and carbon tetrachloride, , the molecule having a non-zero dipole moment is:

40. The same sample of -bromobutane is treated under the two conditions shown.

Which evaluation is appropriate?

41. An alkyl bromide containing four carbon atoms undergoes Wurtz coupling with itself. The coupled alkane contains:

42. A facility uses a volatile chlorinated solvent and also handles a persistent organohalogen pesticide. Which management plan best addresses both immediate and long-term risks?

43. Which alkyl halide can give normal hexane as the single symmetrical hydrocarbon product in a Wurtz reaction?

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

45. Study the following descriptions of a halogen substituent on benzene.

The appropriate evaluation is:

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

47. Use the graph description below. Two reaction-coordinate curves represent ionisation of a tertiary alkyl bromide and a primary alkyl bromide in the same polar protic solvent. The tertiary-substrate curve has a lower first energy maximum. The best interpretation is:

48. The correct order of events in the early stages of methane chlorination is:
P. A methyl radical reacts with .
Q. A chlorine radical abstracts hydrogen from methane.
R. The bond undergoes homolytic cleavage.

49. Arrange the following stages in the correct order for preparing a carboxylic acid from an alkyl halide through a Grignard reagent.
P. The alkyl halide reacts with magnesium in dry ether.
Q. The Grignard reagent attacks carbon dioxide.
R. A magnesium carboxylate is formed.
S. Acidic hydrolysis gives the carboxylic acid.

50. Complete homolytic cleavage of of produces how many moles of chlorine radicals?