Hydrocarbons Mock Test – Class 11 Chemistry

1. The dihedral angle between a front bond and the nearest rear bond is in an eclipsed ethane conformation. In the nearest staggered conformation, it becomes

2. Electrolysis of a single carboxylate salt by the Kolbe method most directly gives an alkane with

3. A learner says, “All staggered conformations of butane must have identical stability because staggered ethane does.” The best correction is that

4. One mole of ethyne, , is completely hydrogenated to ethane, . The amount of required is

5. A methane-ethene gas mixture of gives of on complete combustion. The same mixture is passed over , and only the ethene reacts. The moles of consumed are

6. The unusually high stability of benzene compared with a hypothetical cyclohexatriene is mainly due to

7. Benzene and cyclohexene form a mixture that consumes of in a rapid addition test, while complete combustion of the mixture gives of . The moles of benzene in the mixture are

8. The reaction is best described as

9. A graph is drawn for a straight-chain alkene series with carbon number on the horizontal axis and boiling point on the vertical axis. The best broad interpretation of the graph is

10. A compact comparison of sodium acetate reactions is given below.

The hydrocarbon products of Route P and Route Q are respectively

11. In the same relative-rate comparison of toluene, benzene, and nitrobenzene, the lowest bar should correspond to

12. A hydrogen atom attached to a carbon bonded to two other carbon atoms is described as a

13. The reduction of with a suitable reducing agent gives

14. Friedel-Crafts acylation differs from Friedel-Crafts alkylation because acylation introduces

15. A compound is described as a cycloalkane containing carbon atoms in a ring. The name should begin with

16. The graph-based statement that best matches ethane conformational analysis is

17. A table of directing effects is given below.

The row that needs correction is

18. Nitration and flame observations identify compound , formula , which burns with a smoky flame and gives one mononitro product with . The most suitable identity is

19. Bromine water is commonly used as a simple test for unsaturation because alkenes

20. For the reaction , the role of is best described as

21. Kolbe electrolysis prepares alkanes by electrolysing sodium or potassium salts of carboxylic acids, mainly through

22. A terminal alkyne is converted into an alkane through complete hydrogenation. In the reaction , the carbon skeleton is

23. A table of soda-lime decarboxylation products is given below.

The row that is least suitable as an alkane-product entry is

24. Assertion: A methyl group directs incoming electrophiles mainly to ortho and para positions in benzene substitution.
Reason: The methyl group increases electron density at ortho and para positions through electron-releasing effects.

25. Match each formula with the most suitable first-level description.

26. Complete hydrogenation of ethyne gives

27. The repeating unit of polyethene formed from ethene is best represented as

28. A student says, “If a group is deactivating, it must always be meta-directing.” The best correction is that

29. The role of in bromination of benzene is best described as

30. A desired alkane is propane, . Wurtz preparation from a single alkyl halide is not the best direct choice because

31. The alkane formed by soda-lime decarboxylation of sodium propionate, , is

32. A conformational-energy graph for ethane is described as follows: maxima occur at , , and ; minima occur at , , and . The conformation at is

33. In the monochlorination of propane, substitution at a terminal carbon gives

34. A compound gives a red precipitate with ammoniacal cuprous chloride. The most likely structural feature is

35. Vigorous side-chain oxidation of hydrocarbon , formula , gives of benzoic acid, . If one molecule of gives one molecule of benzoic acid, the moles of oxidised are

36. Assertion: Soda-lime decarboxylation of sodium acetate gives methane.
Reason: In soda-lime decarboxylation, the carbon atom of the group is not retained in the alkane.

37. The general Wurtz reaction for a single alkyl halide is best represented as

38. Combustion data for an unknown open-chain hydrocarbon show that of gives of and of . Complete hydrogenation of the same amount of consumes of . The most suitable formula and unsaturation type of are

39. Consider these statements about chain isomerism in alkanes.
I. Chain isomers have the same molecular formula.
II. Chain isomers differ in the arrangement of the carbon skeleton.
III. has no chain isomers because all alkanes are saturated.

40. A claim says, “The formula proves a compound is but--yne.” The better conclusion is that

41. A reaction note uses the symbol . This notation represents

42. A reaction planner wants to prepare as one of the major ring-substitution products. The starting aromatic compound and reagent set most consistent with this goal is

43. A step in a radical mechanism is written as . This step is classified as

44. Reductive ozonolysis of hydrocarbon gives and . A sample of is completely ozonolysed. The total mass of carbonyl products formed is

45. The general formula of an open-chain monoalkene is

46. Assertion: Wurtz reaction is especially useful for preparing symmetrical alkanes.
Reason: Two identical alkyl halide molecules couple to give one main product.

47. The decolourisation of dilute alkaline by an alkene is used as a test for

48. A table compares alkyne acidity observations.

The row that needs correction is

49. The catalyst commonly used in Friedel-Crafts alkylation is

50. A table compares physical-property statements for alkenes.

The row that needs correction is