Class 11 Chemistry — Chapter 13: Hydrocarbons Online Test

1. The term "polynuclear" in refers to the presence of:

2. The primary reason the Methyl group () is an activating and -directing group is its ability to donate electrons via:

3. When the product of a Friedel–Crafts acylation () is treated with and concentrated (Clemmensen Reduction), the final product obtained is a:

4. The final step in the halogenation mechanism is the regeneration of the catalyst and the aromatic ring. This involves the removal of which species from the complex?

5. In the reaction , the bond of the benzene ring is broken, and a new bond is formed. This step is a characteristic of:

6. The overall nitration reaction is written as: . How is this reaction classified in terms of heat change?

7. The initial slow step in the mechanism of benzene nitration involves the attack of the electrophile on the benzene ring to form:

8. The addition of water () to Ethyne () in the presence of and yields an intermediate enol, which quickly tautomerizes to form the final product:

9. After an alkyne salt () is formed using , how is the neutral terminal alkyne () typically regenerated?

10. Starting with 1,1-Dichloropropane and performing double dehydrohalogenation, what is the final alkyne product?

11. The carbon atoms involved in the triple bond of an alkyne are linked by which combination of bonds?

12. Ozonolysis of an unknown alkene yields () and (). Identify the structure of the starting alkene.

13. Halogenation of an alkene with or results in the formation of which type of product?

14. The conversion of a vicinal dihalide () to an alkene requires treatment with:

15. The compound 2,3-Dimethylbut-2-ene does not show geometrical isomerism because:

16. The two carbon atoms involved in the double bond of an alkene are linked by which combination of bonds?

17. Decarboxylation is considered a useful method for:

18. What is the molecular formula for -Hexane?

19. What is the approximate bond length in a typical alkyne, such as Ethyne ()?

20. How many sigma () and pi () bonds are present in Propene ()?

1. The electrophilic substitution reactions are characteristic of aromatic compounds because:

2. Ozonolysis of an unknown alkene yields () and (). Identify the structure of the starting alkene.

3. According to Markownikov's rule, the major product formed when is added to 2-Methylpropene () is:

4. The -electron count for the Pyridine molecule () is:

5. The primary reason why many larger PAHs, such as Benzo[a]pyrene, are potent carcinogens is that they:

6. The bond angle around the carbon atoms of the double bond in an alkene is approximately:

7. What is the main limitation of the Wurtz reaction for the preparation of alkanes?

8. Hydrocarbons containing carbon-carbon double bonds are classified as:

9. Which of the following classes of hydrocarbons is generally called Paraffins?

10. According to Hückel's Rule, which of the following -electron counts is characteristic of an anti-aromatic compound?

11. Naphthalene (), the simplest PAH, is composed of how many fused benzene rings?

12. In the reaction of Benzene with 1-Chloropropane and , the major product obtained is Isopropylbenzene (Cumene), not Propylbenzene. This is a direct consequence of:

13. What is the molecular formula for the straight-chain alkane known as Heptane?

14. Due to the bond, rotation about the carbon-carbon double bond in alkenes is:

15. Which reagent can be used to distinguish between a terminal alkyne (like Prop-1-yne) and an internal alkyne (like But-2-yne)?

16. What is the general molecular formula for an acyclic alkyne containing one carbon-carbon triple bond?

17. The terminal hydrogen atom of ethyne () is acidic because the carbon atom involved is:

18. Which of the following compounds would require a high temperature and high pressure for substitution with an aqueous base ()?

19. The reaction of Ethyne with cold, dilute (Bayer's reagent) yields which product?

20. Polymerization is generally defined as a chemical process where:

21. Which of the following -electron counts for a planar, cyclic, fully conjugated system would result in the greatest destabilization (anti-aromaticity)?

22. What is the general molecular formula for saturated open-chain hydrocarbons (Alkanes)?

23. Fluorination of benzene is typically avoided in a laboratory setting because the reaction is:

24. The first molecule of is added to an alkyne following which rule?

25. Which rule governs the major product formed during the dehydrohalogenation (removal of ) of a secondary alkyl halide?

26. Unlike the purely cationic sigma complexes formed in Nitration or Halogenation, the sigma complex intermediate formed during the Sulfonation of Benzene is best described as:

27. Which of the following substituents is categorized as a deactivating and -directing group?

28. The reaction of Ethyne with hydrogen gas () in the presence of Nickel () catalyst yields which final product?

29. When an unsymmetrical alcohol like Pentan-2-ol is dehydrated, which type of alkene is predominantly formed?

30. The electrolysis of an aqueous solution of sodium ethanoate () using the Kolbe's method produces which main product at the anode?

1. The addition of to 2-Methylpropene () follows Markownikov's rule. What is the structure of the carbocation intermediate?

2. Which product is formed when is added to a terminal alkyne like Prop-1-yne in the presence of and ?

3. The electrophile that attacks the benzene ring during the sulfonation reaction is the:

4. What distinguishes a cis-isomer from a trans-isomer in a disubstituted alkene?

5. The formation of Polyethylene from Ethene is an example of which type of polymerization reaction?

6. What is the molecular formula for -Hexane?

7. The second elimination step, converting a haloalkene into an alkyne, is often difficult because it removes a hydrogen from a carbon that is part of a double bond. What extremely strong base is required to complete this step, especially for terminal alkynes?

8. Which of the following is the monomer used to produce Polyvinyl Chloride (PVC)?

9. What is the final step in the electrophilic substitution mechanism, which re-establishes the aromaticity of the ring?

10. Which type of hydrogen atom in an alkane is most easily substituted by a halogen atom () in a free-radical halogenation reaction?

11. The reaction of Prop-1-yne () with Tollen's reagent produces:

12. A simple method often used to remove PAHs from contaminated water or industrial effluents relies on their property of being:

13. Which set of reagents is used to convert an alkene to a corresponding alkane?

14. The two carbon atoms involved in the double bond of an alkene are linked by which combination of bonds?

15. Which catalyst system is typically used in the industrial production of to create a highly linear polymer chain with minimal branching?

16. What is the correct IUPAC name for the compound ?

17. Which statement accurately describes the relationship between -Hexane and 2-Methylpentane?

18. The initial step in the sulfonation of benzene involves the attack of the electrophile on the -cloud of benzene, forming an intermediate known as a:

19. Friedel–Crafts Acylation requires more than one full equivalent of the catalyst (often to equivalents). This is because:

20. Which of the following intermediates is formed at the anode during the Kolbe's electrolytic synthesis of alkynes?

21. Why are halogens (, ) unique among all substituents?

22. Which of the following human activities is LEAST likely to produce or expose individuals to significant amounts of PAHs?

23. Chain isomerism is not possible for which of the following simple alkanes?

24. A compound with the molecular formula can represent either a simple alkyne or:

25. Incomplete combustion of alkanes, which occurs due to a limited supply of oxygen, typically leads to the formation of:

26. The Kekulé structure of benzene proposed that the molecule has:

27. Due to the bond, rotation about the carbon-carbon double bond in alkenes is:

28. The halogenation of alkanes (e.g., chlorination in the presence of sunlight) proceeds through which general reaction mechanism?

29. Benzene is best represented by the resonance hybrid structure because:

30. The nitrating mixture is formed by the equilibrium reaction: . Which substance acts as the base in this equilibrium?

31. The nitration of benzene is an example of which general class of organic reaction?

32. What is the necessary condition or reagent (Z) to carry out the following transformation from Chlorobenzene to Benzene?

33. When But-2-ene () undergoes ozonolysis, the single organic product obtained after reductive workup is:

34. What is the correct IUPAC name for the aromatic compound with two nitro groups attached to the benzene ring at positions 1 and 4?

35. The addition of water () to Ethyne () in the presence of and yields an intermediate enol, which quickly tautomerizes to form the final product:

36. If Nitrobenzene is subjected to further nitration, the incoming nitro group will predominantly substitute at which position?

37. Polymerization is generally defined as a chemical process where:

38. The dehydrohalogenation of a terminal geminal dihalide (1,1-dihalide) primarily yields which type of alkyne?"

39. What is the main limitation of the Wurtz reaction for the preparation of alkanes?

40. In the Molecular Orbital (MO) model of Benzene, the six -orbitals on the carbon atoms combine to form how many bonding molecular orbitals?

41. The stability of the Benzene ring is due to the fact that all six carbon atoms are:

42. Predict the final organic product (P) of the following sequence:

43. Which of the following substrates will fail to undergo Friedel–Crafts acylation ()?

44. The product of a Friedel–Crafts Acylation is generally less reactive toward a second electrophilic substitution than the starting benzene ring. This is due to the acyl group () being a:

45. Ozonolysis of Cyclohexene followed by reductive workup yields a single product, which is a:

46. Ethene () is the simplest alkene. Which of the following is true about its structure?

47. Which pair of compounds represents functional group isomerism?

48. Why is benzene significantly more stable than a hypothetical cyclohexatriene structure with isolated double bonds?

49. Which of the following reagents will react with But-1-yne but not with But-2-yne?

50. The lack of free rotation about a bond, as opposed to a bond, leads to which specific type of isomerism?