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

2. Which of the following compounds exhibits geometrical (cis-trans) isomerism?

3. In an organic compound containing both a double bond and a triple bond, which functional group is prioritized in determining the parent chain and the suffix?

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

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

6. What is the minimum number of carbon atoms required for an alkene to exhibit positional isomerism?

7. The complex formed between the Lewis acid () and the halogen () that generates the electrophile can be represented as:

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

9. What is the function of the zinc dust () and water workup () step after the initial reaction of the alkene with ozone ()?

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

11. Aromatic hydrocarbons generally burn with a characteristic yellow, sooty flame. This is primarily due to:

12. Which pair of compounds represents functional group isomerism?

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

14. When Methane is heated with oxygen at high pressure () in the presence of Copper () catalyst, the primary product is:

15. The lack of free rotation about the carbon-carbon double bond in alkenes is responsible for which type of isomerism?

16. The structure of Benzene is best represented by a resonance hybrid of the two structures proposed by:

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

18. What is the sum of the stoichiometric coefficients of and in the balanced equation for the complete combustion of Propane ()?

19. Which of the following compounds is an example of a polycyclic aromatic hydrocarbon (PAH) known for its high carcinogenic potential?

20. As a result of chain isomerism, how do the boiling points of the isomers generally change from the straight chain to the highly branched chain?

21. Which of the following is a disadvantage of the Kolbe's electrolytic synthesis method for preparing alkanes?

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

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

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

25. What are the products of the ozonolysis of 2-Methylbut-2-ene ()?

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

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

28. What is the hybridization state of the two carbon atoms involved in the double bond of an alkene?

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

30. The primary difference between a homopolymer (like polyethylene) and a copolymer is:

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

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

3. A compound is classified as non-aromatic if:

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

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

6. Which product is formed when Ethyne (Acetylene) is passed through a red-hot iron tube at ?

7. The decomposition of a higher alkane into a mixture of lower alkanes, alkenes, and hydrogen by heating it to a high temperature is called:

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

9. How many total bonds and bonds are present in a molecule of But-2-yne ()?

10. The addition of to Ethene is a test for unsaturation. The mechanism for this reaction is an example of:

11. Anthracene () is a three-ring PAH. Compared to its isomer, Phenanthrene, Anthracene is generally considered to be:

12. Why does the Friedel–Crafts Alkylation reaction often result in polysubstitution (addition of multiple alkyl groups)?

13. Identify the total number of primary carbon atoms in the structure of 2,2-Dimethylpropane (Neopentane).

14. Which catalyst is used to selectively stop the hydrogenation of an alkyne at the alkene stage (i.e., synthesize an alkene from an alkyne)?

15. 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:

16. Which of the following compounds is an example of a polycyclic aromatic hydrocarbon (PAH) known for its high carcinogenic potential?

17. The -electron count in the smallest aromatic PAH, Naphthalene, is:

18. How are the substituents listed in the final IUPAC name if there are multiple different alkyl groups (e.g., methyl and ethyl)?

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

20. If a benzene ring is substituted with both a group (strongly activating, ) and a atom (deactivating, ), where will the next electrophile predominantly substitute?

21. What is the IUPAC name for the structure ?

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

23. What is the principal functional group or structural feature that determines the suffix '-ene' in the IUPAC naming of an organic compound?

24. The Cyclopropenyl cation (a three-membered ring with one positive charge) is aromatic because it satisfies Hückel's rule with which total number of electrons?

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

26. Which of the following constitutional (structural) isomers of has a four-carbon parent chain?

27. Which of the following is an example of an addition polymerization reaction involving an alkene?

28. According to Hückel's rule, for a compound to be considered aromatic, the number of electrons in the fully conjugated cyclic system must satisfy which formula?

29. What is the approximate bond angle in a simple, unsubstituted alkane like Methane ()?

30. Which of the following is a disadvantage of the Kolbe's electrolytic synthesis method for preparing alkanes?

31. What is the major product (M) of the reaction when Benzene is treated with in the presence of anhydrous , followed by and ?

32. Dehydrohalogenation of an unsymmetrical vicinal dihalide (e.g., 1,2-Dibromobutane) will preferentially form the internal alkyne (But-2-yne) over the terminal alkyne (But-1-yne). This is because the internal alkyne is:

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

34. If Toluene is sulfonated at a low temperature (e.g., ), the major product is primarily the isomer. If the temperature is raised to , the major product shifts to the isomer. This phenomenon is an example of:

35. The benzenesulfonic acid product can be readily converted into phenol () by first treating it with at high temperatures, followed by acidification. This conversion highlights the utility of the group as:

36. What is the number of sigma bonds in the molecule -Butane ()?

37. What are the products of the ozonolysis of 2-Methylbut-2-ene ()?

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

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

40. The reduction of an alkyne with metal dissolved in liquid () primarily yields which isomeric product?

41. How many bonds and bonds are present in the benzene molecule ()?

42. What is the hybridization state of the two carbon atoms involved in the double bond of an alkene?

43. Which of the following compounds will not exhibit geometrical (cis-trans) isomerism?

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

45. What is the common name of the alkane with four carbon atoms that exhibits chain isomerism with -Butane?

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

47. The preference of alkanes to undergo substitution reactions rather than addition reactions is due to:

48. What is the hybridization of the carbon atoms in the Polyethylene polymer chain?

49. If the nitration of Toluene () is performed, the major products formed will be:

50. The electrophile that attacks the benzene ring during the nitration reaction is: