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

2. The correct representation of the -electron system in Benzene according to the Modern Theory is:

3. When naming a substituted benzene derivative, the two substituents are at the 1 and 3 positions. Which common prefix is used to denote this arrangement?

4. Which of the following reaction types is classified as a -elimination reaction?

5. The primary purpose of ozonolysis ( followed by ) in alkene chemistry is to:

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

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

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

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

10. Which pair of compounds represents functional group isomerism?

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

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

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

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

15. Desulfonation (the reversal of sulfonation) is often used in synthesis for which of the following purposes?

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

17. Which of the following PAHs is considered one of the most potent carcinogens and is found in high concentrations in cigarette smoke and coal tar?

18. Which of the following is an essential condition for two organic compounds to be structural isomers?

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

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

21. The dehydration of an alcohol to form an alkene is typically carried out using which type of reagent and condition?

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

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

24. Which of the following statements regarding the structure of Benzene is correct?

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

26. A compound with the molecular formula can be either an alkene or a cycloalkane. This is an example of which type of isomerism?

27. In the decarboxylation reaction using soda lime, the role of Calcium Oxide () is primarily to:

28. Which type of hybridization is observed for all carbon atoms in the simplest member of the Alkyne family, Ethyne ()?

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

30. The hybridization of the carbon atoms involved in the triple bond of an alkyne is:

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

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

3. What is the molecular formula for Hex-1-yne?

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

5. 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?

6. The initial, slower step in the reaction between benzene and is rate-determining. This involves the breaking of the aromaticity and has a high activation energy, characteristic of:

7. An alkene yields one mole of and one mole of (Methyl Ethyl Ketone) upon ozonolysis. What was the starting alkene?

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

9. In the decarboxylation reaction using soda lime, the role of Calcium Oxide () is primarily to:

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

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

12. 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?

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

14. 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:

15. The carbon-carbon triple bond length in Ethyne () compared to the double bond length in Ethene () and the single bond length in Ethane () is:

16. The reaction of an alkene with cold, dilute, aqueous (Bayer's reagent) leads to the formation of which class of compounds?

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

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

19. Which pair of compounds represents an example of chain isomerism?

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

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

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

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

24. What is the approximate length of the carbon-carbon bonds in the stable benzene ring?

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

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

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

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

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

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

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

32. What is the minimum number of carbon atoms required for a compound to be classified as an alkyne?

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

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

35. The free rotation about the single bond in alkanes leads to the existence of different spatial arrangements known as:

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

37. Which type of orbital overlap forms the bond component of an alkene's double bond?

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

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

40. What is the geometry and bond angle around the carbon atoms of the triple bond in a simple alkyne?

41. Which of the following alkanes can be prepared in good yield by the Wurtz reaction using only a single type of alkyl halide?

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

43. 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:

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

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

46. The mechanism by which is damaged by the reactive metabolites of PAHs is termed:

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

48. How many hydrogen atoms are present in a straight-chain alkane molecule that contains 8 carbon atoms?

49. When 2-Bromobutane is treated with a strong base (like alcoholic ), which alkene is the major product according to Saytzeff's rule?

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