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

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

3. Which reagent combination is typically used for the decarboxylation of a sodium carboxylate salt () to form an alkane?

4. Which type of isomerism is characterized by having the same molecular formula and the same carbon skeleton, but differing in the position of the functional group or substituent?

5. All -directing groups are characterized by having:

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

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

8. 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:

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

10. Which factor is most important in determining whether the dehydration of an alcohol will follow the or mechanism?

11. The compound Cyclooctatetraene () has electrons. Why is it considered non-aromatic rather than anti-aromatic?

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

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

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

15. What is the general molecular formula for acyclic alkynes containing one carbon-carbon triple bond?

16. The carbon atoms in an alkane chain are joined by which type of bond?

17. What is the IUPAC name for the structure ?

18. The product formed when sodium propanoate () is heated with soda lime ( and ) is:

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

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

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

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

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

24. The sulfonation of benzene is best carried out using which reagent system to maximize the yield of benzenesulfonic acid?

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

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

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

28. 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?

29. Which intermediate species is generated at the anode during the Kolbe's electrolytic synthesis of alkanes?

30. Sulfonation is a unique electrophilic substitution reaction because it is a highly reversible process. What governs the reversal of this reaction (desulfonation)?

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

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

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

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

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

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

7. The preparation of an alkyne from a vicinal dihalide involves the sequential elimination of two molecules of . Which type of reaction mechanism is involved in these elimination steps?

8. When Propyne is treated with dilute in the presence of (Kucherov's reaction), the final stable product obtained is:

9. Ozonolysis of 2-Butene () followed by treatment with yields which product?

10. What is the general molecular formula for acyclic alkenes containing one carbon-carbon double bond?

11. What is the molecular formula for -Hexane?

12. The reaction of an internal alkyne with in an inert solvent results in the formation of a product with which stereochemistry?

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

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

15. The carbon atoms at the ends of a straight-chain alkane are termed as:

16. What is the molecular formula for Cyclopentene?

17. What is the product formed after the first stage of chlorination of Methane () in the presence of UV light?

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

19. According to Molecular Orbital theory, the six electrons in benzene are delocalized over how many carbon atoms?

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

21. Ozonolysis of Propene () followed by reductive workup yields which two main products?

22. The decolorization of an aqueous solution of cold, dilute, alkaline potassium permanganate ( reagent) is a characteristic test for the presence of:

23. Kolbe's electrolytic method for the preparation of alkynes involves the electrolysis of the potassium or sodium salt of which specific class of organic compounds?

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

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

26. The conversion of a higher alkane into an isomeric branched-chain alkane in the presence of an anhydrous aluminum chloride and hydrogen chloride is called:

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

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

29. 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:

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

31. 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:

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

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

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

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

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

37. Which reagent combination is typically used for the decarboxylation of a sodium carboxylate salt () to form an alkane?

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

39. Which of the following pair of compounds are chain isomers of Octane ()?

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

41. A hydrocarbon has the molecular formula . How many possible positional isomers are there if the parent chain is kept as a straight chain (Hexane)?

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

43. 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:

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

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

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

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

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

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

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