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. Polynuclear Aromatic Hydrocarbons (PAHs) are primarily formed during:

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

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

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

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

6. The two carbon atoms involved in the double bond of an alkene are linked by which combination of bonds?

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

8. 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:

9. How many total bonds and bonds are present in a molecule of Propene ()?

10. Why are halogens (, ) unique among all substituents?

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

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

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

14. When Prop-1-yne is hydrated (), the final product is (Acetone). This is because the initial addition follows Markownikov's rule, placing the group on:

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

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

17. What is the sum of the stoichiometric coefficients of and in the balanced chemical equation for the complete combustion of Pentane ()?

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

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

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

21. The primary difference between a homopolymer (like polyethylene) and a copolymer is:

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

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

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

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

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

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

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

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

30. Hydrocarbons are primarily composed of which two elements?

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

2. But-1-yne and Buta-1,3-diene are examples of which type of isomerism?

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

4. The formation of Polyethylene from Ethene is an example of which type of polymerization reaction?

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

6. A compound is classified as non-aromatic if:

7. How many total bonds and bonds are present in a molecule of Propene ()?

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

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

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

11. Alkynes are classified as terminal or internal based on:

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

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

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

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

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

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

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

19. Which set of reagents (R) is best suited to convert Benzaldehyde () to Benzene?

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

21. 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:

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

23. 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:

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

25. Which reagent is typically used for the halogenation (e.g., chlorination) of Benzene to prevent addition and favor substitution?

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

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

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

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

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

31. 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?

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

33. Which of the following is the monomer used to produce Polyvinyl Chloride (PVC)?

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

35. What is the minimum number of carbon atoms required for an alkene to exhibit positional isomerism?

36. 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:

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

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

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

40. What is the IUPAC name for the structure ?

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

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

43. What is the molecular formula for Cyclopentene?

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

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

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

47. 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:

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

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

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