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 resonance energy of Benzene, which quantifies its extra stability due to delocalization, is approximately:

2. If the temperature is too high during the nitration of benzene, the formation of which product is favored?

3. All -directing groups are characterized by having:

4. What is the correct IUPAC name for the terminal alkyne structure ?

5. What is the essential purpose of using concentrated sulfuric acid () along with concentrated nitric acid () in the nitration of benzene?

6. A significant limitation shared by both Friedel–Crafts alkylation and acylation is that the reaction:

7. Which of the following best describes the geometry around the triple bond in an alkyne?

8. Which type of addition is characteristic of the reaction of with an alkene in an inert solvent?

9. Consider the reaction where Benzoic Acid is treated with concentrated and . The major product formed is (W). What is the orientation of the group in (W)?

10. Polyethylene (PE) is formed from the monomer Ethene. What is the repeating structural unit in the Polyethylene chain?

11. Which of the following is the condition for a pair of compounds to be metameric isomers?

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

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

14. Alkynes are classified as terminal or internal based on:

15. Which of the following species is an example of an anti-aromatic compound?

16. How many possible structural (chain and positional) isomers are there for the alkane with the molecular formula (Hexane)?

17. Which of the following conditions is most suitable for the dehydrohalogenation of an alkyl halide ()?

18. What is the approximate bond length in a typical alkene, such as Ethene ()?

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

20. Halogenation of benzene requires high heat or UV light in the absence of a Lewis acid catalyst to promote:

21. How many bonds and bonds are present in the molecule Propyne ()?

22. The halogenation of benzene is an irreversible process under standard conditions, primarily due to:

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

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

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

26. What is the main limitation of the Wurtz reaction when attempting to prepare an unsymmetrical alkane, such as Propane?

27. The halogenation of benzene requires a catalyst, specifically a Lewis acid, because:

28. What are the products of the complete combustion of any alkane in the presence of excess oxygen?

29. For the aromatic compound Naphthalene (), what is the value of 'n' in Hückel's rule ( electrons)?

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

1. What is the IUPAC name of the product obtained when Ethyne reacts with excess Bromine water ( in )?

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

3. The difference between any two consecutive members in the Alkane homologous series is a unit of:

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

5. The halogenation of alkanes (e.g., Chlorination of Methane) is an example of which type of organic reaction mechanism?

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

7. Which of the following conditions favors the highest yield of mononitration of benzene?

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

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

10. Which halogen reacts the fastest with methane in a free-radical substitution reaction?

11. What is the correct IUPAC name for the alkane structure ?

12. An activating group is defined as a substituent that:

13. Which type of addition is characteristic of the reaction of with an alkene in an inert solvent?

14. The single bond length in propane is . This bond is formed by the overlap of which types of orbitals from the two adjacent carbon atoms?

15. Which pair of compounds represents functional group isomerism?

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

17. Which reaction is used to selectively form a cis-alkene from an alkyne?

18. Polyvinyl Chloride (PVC) is considered a thermoplastic material, meaning it:

19. Which of the following numbers of electrons is consistent with Hückel's rule for an aromatic compound?

20. How many possible structural isomers exist for Dimethylbenzene (Xylene)?

21. The reaction of an alkene with hydrogen gas () in the presence of a metal catalyst (, , or ) is known as:

22. Which reagent is typically used for the halogenation (e.g., chlorination) of Benzene to prevent addition and favor substitution?

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

24. If an excess amount of Chlorine gas () is reacted with Methane () under high temperature or light, the final product of complete substitution is:

25. Hydrocarbons are primarily composed of which two elements?

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

27. The intermediate formed by the reaction of the electrophile () and the benzene ring is known as the complex. This intermediate is stabilized by:

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

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

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

31. Halogenation of benzene requires high heat or UV light in the absence of a Lewis acid catalyst to promote:

32. How many possible structural (chain and positional) isomers are there for the alkane with the molecular formula (Hexane)?

33. How many bonds and bonds are present in the molecule Propyne ()?

34. The treatment of Ethyne () with a hot iron tube at results in which major product?

35. The alkene that yields only (Acetone) upon ozonolysis is:

36. When a substituent donates electrons to the ring via resonance, the electron density is primarily increased at which positions?

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

38. The intermediate compound formed immediately after the reaction of an alkene with ozone () but before the workup is called a:

39. The cyclopentadienyl anion (a five-membered ring with one negative charge) is aromatic because it is cyclic, planar, fully conjugated, and contains:

40. In Kolbe's synthesis of Ethyne (), the starting material is the potassium or sodium salt of which parent acid?

41. The addition of to Propene () follows which of the following rules for predicting the major product?

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

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

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

45. The hydrogenation of -Xylene () using and under mild conditions results in what major product (L)?

46. What is the sum of the stoichiometric coefficients of and in the balanced chemical equation for the complete combustion of Pentane ()?

47. 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:

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

49. The resonance energy of benzene is approximately . This high resonance energy indicates that benzene is:

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