Haloalkanes and Haloarenes Mock Test – Class 12 Chemistry

1. Resonance in chlorobenzene involves:

2. 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:

3. A graph shows cumulative gas volume against time while an aromatic diazonium tetrafluoroborate is heated. If decomposition goes to completion, the curve should:

4. In the reaction , the leaving group is:

5. Why can a small amount of chlorine released from chlorofluorocarbons destroy a much larger amount of ozone?

6. Study the following features of DDT.

The appropriate evaluation is:

7. The best condition for converting -bromopropane mainly into propan--amine while limiting further alkylation is:

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

9. A laboratory needs to convert an alcohol into an alkyl chloride. The product must be separated with minimal contamination by non-volatile inorganic by-products. The most appropriate choice is:

10. Under Lucas-type conditions, the broad order of reaction rate for simple alcohols is:

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

12. Reaction of -chlorobutane with gives a nitroalkane containing:

13. The temperature during diazotisation of aniline is maintained near mainly because:

14. Assertion: can convert ethanol into chloroethane.
Reason: The carbon skeleton of ethanol is lengthened by one carbon during the reaction.

15. A sample of carbon tetrachloride has molar mass . How many moles of chlorine atoms are present?

16. During selective bromination of propane, a bromine radical removes the hydrogen from the middle carbon and forms the radical . Its next propagation reaction produces:

17. Compared with a carbon–chlorine bond in a similar ordinary alkyl chloride, the carbon–chlorine bond in vinyl chloride is generally ______.

18. The balanced equation for converting an alcohol into an alkyl chloride using thionyl chloride is:

19. Under identical conditions, the rate constants for benzyl bromide and bromoethane are and , respectively. At equal substrate and nucleophile concentrations, the benzyl bromide reaction is faster by a factor of:

20. A student compares boiling and melting trends using the table below.

The appropriate conclusion is:

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

22. Four cyanide-substitution records are shown.
P. gives .
Q. gives .
R. gives .
S. gives .

Choose the appropriate evaluation.

23. Bromobenzene is treated separately with two metals in dry ether.

Vessel P contains sodium.
Vessel Q contains magnesium.

The expected principal products are:

24. Match each stereochemical term in Column I with its meaning in Column II.

25. A reaction-coordinate graph for benzene chlorination shows two pathways with the same reactant and product energy levels. The curve for the -catalysed pathway has a lower maximum than the uncatalysed curve. The graph indicates that :

26. A graph compares carbon–chlorine bond dissociation enthalpy for ethyl chloride and vinyl chloride. The bar for vinyl chloride is expected to be:

27. A student attempts to prepare ethylmagnesium bromide using freshly distilled bromoethane but a flask that was rinsed with water and not dried. The most likely outcome is:

28. Use the following arrangement around a tetrahedral carbon:
P.
Q.
R.
S.

Interchanging any two groups once produces:

29. The molecule is achiral because the chlorine-bearing carbon:

30. 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.

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

32. The most reliable way to select between and for a proposed haloalkane reaction is to:

33. Match each structure in Column I with its classification in Column II.

34. Which comparison of ordinary nucleophilic-substitution behaviour is most accurate?

35. Chlorocyclohexane is classified as a secondary haloalkane because the ring carbon bonded to chlorine:

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

37. The most suitable conversion plan for preparing bromobenzene from aniline is:

38. A diazonium route is especially valuable when a halogen must be introduced at a position already occupied by an amino group because:

39. An aryl halide and an alkyl halide are heated with sodium in dry ether to form an alkyl-substituted aromatic hydrocarbon. This coupling is called:

40. Which equation represents reduction of a haloalkane to a hydrocarbon?

41. Ethanol is often added in small quantity to stored chloroform because ethanol:

42. For a one-step nucleophilic displacement requiring direct approach to the carbon bearing bromine, the least sterically hindered substrate is:

43. Pyridine may be used during an alcohol–thionyl chloride reaction mainly to:

44. Assertion: The useful peroxide effect is observed characteristically with , but not with or .
Reason: Both propagation steps are energetically favourable for the radical chain, whereas a required propagation step becomes unfavourable for or .

45. Sodium ethoxide reacts with bromoethane according to the Williamson ether synthesis. The principal organic product is:

46. 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.

47. Further alkylation of a primary amine is possible mainly because the primary amine:

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

49. Match each property in Column I with the appropriate description in Column II.

50. A student states, “The carbon atom of is electrophilic because it is bonded to a metal.” The best correction is: