Haloalkanes and Haloarenes Mock Test – Class 12 Chemistry

1. Study the two reactions below.

The appropriate evaluation is:

2. Arrange the following stages in the correct order for a rearranged substitution.
P. The leaving group departs and forms an initial carbocation.
Q. A -hydride or alkyl shift produces a more stable carbocation.
R. The nucleophile attacks the rearranged carbocation.
S. Proton transfer gives a neutral product when the nucleophile is neutral.

3. Match each reagent or reagent system in Column I with the corresponding result in Column II.

4. Match each item in Column I with the appropriate description in Column II.

5. Inspect the following reaction-planning assignments.

The appropriate evaluation is:

6. The combined electrophilic and nucleophilic substitution description that fits haloarenes is:

7. A molecule has the formula . Its most suitable classification by halogen count is:

8. 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.

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

The best interpretation is:

10. 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:

11. 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:

12. A tetrahedral carbon atom becomes a stereogenic centre when it is bonded to:

13. For the first step of an reaction, the activation energy is represented by:

14. Aniline is converted into benzenediazonium chloride by treating it with:

15. Freons are broadly classified as compounds containing:

16. Which equation best represents a Swarts reaction using silver fluoride?

17. Use the arrangements described below.

P.
Q.

Which description is correct?

18. In a simplified model, of a chlorofluorocarbon releases one chlorine radical per molecule. Each radical destroys ozone molecules before removal. What mass of ozone is destroyed if the molar mass of ozone is ?

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

20. Iodide is generally a better leaving group than fluoride because:

21. Read the reaction journey below and answer the question.
Aniline is converted into a diazonium salt, then into bromobenzene. Bromobenzene forms phenylmagnesium bromide, which reacts with carbon dioxide and is finally acidified to give benzoic acid.
Select the interpretation of the carbon and nitrogen changes.

22. In a simplified vector model, two equal bond dipoles of act at an angle of . Their resultant magnitude is:

23. Beta-elimination of a haloalkane involves:

24. In an ideal reaction, the haloalkane concentration is decreased by , while the nucleophile concentration is increased by . Temperature remains constant. The ratio of the new rate to the original rate is:

25. Methylmagnesium bromide reacts with water to form:

26. Which reagent sequence converts ethanol into propanenitrile?

27. An reaction produces exactly equal amounts of two enantiomeric products. Assuming no other optically active substance is present, the product mixture will:

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

The appropriate evaluation is:

29. Cyclohexene rapidly decolourises a bromine solution because:

30. The term used for inversion of configuration during backside nucleophilic displacement is:

31. Chlorobenzene usually gives little or no ordinary Friedel–Crafts alkylation with an alkyl chloride and . The most complete explanation is:

32. The compound is best described as:

33. 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.

34. The carbon–chlorine bond in chlorobenzene has partial double-bond character mainly because:

35. 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:

36. During addition of to -methylbut--ene, initial protonation gives a secondary carbocation that can undergo a hydride shift to a more stable tertiary carbocation. The product formed after chloride attack on the rearranged carbocation is:

37. Addition of to but--ene gives only one constitutional bromoalkane because:

38. A sample of bromobenzene forms phenylmagnesium bromide with efficiency. Carboxylation and acidic hydrolysis then convert of that Grignard reagent into benzoic acid. If the molar mass of benzoic acid is , what mass of benzoic acid is obtained?

39. Among the following compounds, the one expected to resist ordinary nucleophilic substitution most strongly is:

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

41. Which pair gives a positive iodoform test under standard iodine–alkali conditions?

42. Three chlorides are compared under substitution conditions:
P.
Q.
R.

The compound in which chlorine is attached to a benzylic carbon is:

43. A substitution rate is unchanged when nucleophile concentration is tripled, but it doubles when haloalkane concentration is doubled. This kinetic behaviour supports:

44. To obtain -dibromoethane from bromoethane, the required sequence is:

45. An unknown liquid is warmed with iodine and alkali. A pale-yellow crystalline precipitate with a characteristic smell appears. The observation most strongly indicates formation of:

46. A reaction mixture contains and . Which set contains all three stable products that can arise from pairwise termination of these radicals?

47. Appraise the following statements.
Statement I: A chiral haloalkane may exist as two non-superimposable mirror images.
Statement II: Every secondary haloalkane is chiral.
Statement III: A tetrahedral carbon with two identical substituents is not a stereogenic centre.

48. Chloroethane and chlorobenzene are separately heated with aqueous alkali under ordinary haloalkane conditions. Chloroethane forms ethanol readily, whereas chlorobenzene shows little reaction. The best combined explanation is:

49. Read the situation below and answer the question.

Compound P is , while compound Q is . Both are heated with alcoholic . Compound Q forms an alkene readily, but P does not undergo ordinary beta-elimination.

Which explanation is correct?

50. A carbon skeleton containing only carbon–carbon single bonds is described as saturated, whereas the presence of a carbon–carbon double bond makes it: