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 general molecular formula for acyclic alkenes containing one carbon-carbon double bond?

2. 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?

3. The lack of free rotation about a bond, as opposed to a bond, leads to which specific type of isomerism?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

19. Which of the following is an advantage of Friedel–Crafts Acylation over Alkylation?

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

21. The second elimination step, converting a haloalkene into an alkyne, is often difficult because it removes a hydrogen from a carbon that is part of a double bond. What extremely strong base is required to complete this step, especially for terminal alkynes?

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

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 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:

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

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

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

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

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

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

1. Which of the following substituents is a strongly activating and -directing group?

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

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

4. If a substituted benzene ring like chlorobenzene is subjected to further chlorination, the second chlorine atom will predominantly substitute at the and positions. This is because:

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

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

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

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

9. Decarboxylation is considered a useful method for:

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

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

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

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

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

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

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

17. When 1-Butene reacts with in the absence of peroxides, the major product is 2-Bromobutane. This is an example of an addition reaction that follows:

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

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

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

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

22. Which of the following statements is true regarding the hybridization in alkanes?

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

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

25. As the degree of branching increases in isomeric alkanes, how does the boiling point generally change?

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

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

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

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

30. Treatment of a terminal alkyne with a strong base like followed by reaction with an alkyl halide () is an effective method for:

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

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

33. 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:

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

35. The alkyl halide used in the Wurtz reaction must be dissolved in which solvent for the reaction to proceed successfully?

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

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

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

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

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

41. 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?

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

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

44. Which pair of compounds represents functional group isomerism?

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

46. The difference between any two consecutive members in the Alkane homologous series is a unit of:

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

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

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

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