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. Which reagent is typically used for the first dehydrohalogenation step when converting a vicinal dihalide (e.g., 1,2-Dibromopropane) into a haloalkene?

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

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

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

6. In the preparation of ethene () via Kolbe's electrolytic method, the starting material is the aqueous solution of the sodium or potassium salt of which carboxylic acid?

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

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

9. 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?

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

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

12. 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)?

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

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

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

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

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

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

19. What is the molecular formula for -Hexane?

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

21. What is the value used in Hückel's rule ( electrons) for the benzene molecule?

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

23. What is the molecular formula for Cyclopentene?

24. 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:

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

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

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

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

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

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

1. A cyclic, planar, fully conjugated system that contains electrons (e.g., electrons) is classified as:

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

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

4. What is the IUPAC name for the structure ?

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

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

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

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

9. 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?

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

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

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

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

14. When is added to an alkene in the presence of an organic peroxide (like benzoyl peroxide), the reaction is said to follow:

15. Which of the following is the standard reagent and catalyst system required for the chlorination of benzene?

16. 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:

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

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

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

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

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

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

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

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

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

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

27. A major limitation of the Friedel–Crafts Alkylation reaction is the possibility of the alkyl group rearranging before attacking the benzene ring. This rearrangement occurs because the electrophile generated is often:

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

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

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

31. 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:

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

33. 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?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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