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

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

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

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

5. 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:

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

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

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

9. Naphthalene (), the simplest PAH, is composed of how many fused benzene rings?

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

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

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

13. The reaction of an alkyne with (Hydrobromination) follows Markownikov's rule. Which product is formed when one equivalent of is added to Propyne ()?

14. Which of the following is not a structural isomer of -Pentane ()?

15. What is the major organic product (X) formed in the following two-step synthesis?

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

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

18. The reaction of Toluene with an excess of Bromine () in the presence of yields the major organic product (Y). What is (Y)?

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

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

21. If 1-Propanol () is dehydrated with concentrated at , what is the product?

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

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

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

25. Terminal alkynes (e.g., Ethyne) are characterized by the presence of an acidic hydrogen atom. The acidity is primarily due to the:

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

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

28. Which product is formed when Propene () reacts with water in the presence of an acid catalyst ()?

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

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

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

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

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

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

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

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

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

9. The Friedel–Crafts Alkylation reaction uses an alkyl halide () and a Lewis acid catalyst to introduce an alkyl group onto a benzene ring. The primary Lewis acid catalyst used is:

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

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

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

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

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

15. Which of the following is not a structural isomer of -Pentane ()?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

31. The conversion of a compound from the enol form to the keto form is an example of which specialized type of isomerism?

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

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

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

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

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

37. In the homologous series of alkanes, what is the increase in molar mass between two consecutive members?

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

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

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

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

42. The bromination of benzene is generally preferred over the chlorination in many laboratory syntheses because:

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

44. The two main types of Polyethylene, Low-Density Polyethylene (LDPE) and High-Density Polyethylene (HDPE), primarily differ in their:

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

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

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

48. What is the approximate range of the degree of polymerization (number of monomer units, ) in commercial polyethylene?

49. The hybridization of all six carbon atoms in the benzene ring is:

50. The nitration of benzene is an example of which general class of organic reaction?