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. 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:

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

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

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

5. A crucial difference in the required starting materials for Alkylation versus Acylation is that Acylation uses an acyl halide () or an acid anhydride, while Alkylation uses:

6. The bond angle around the carbon atoms of the double bond in an alkene is approximately:

7. The number of chain isomers possible for the molecular formula (Pentane) is:

8. In an electrophilic aromatic substitution reaction, a substituent already present on the benzene ring is categorized as an -director or a -director based on:

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

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

11. 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?

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

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

14. When the product of a Friedel–Crafts acylation () is treated with and concentrated (Clemmensen Reduction), the final product obtained is a:

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

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

17. 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?

18. 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)?

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

20. Which type of addition is characteristic of the reaction of with an alkene in an inert solvent?

21. 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:

22. The first molecule of is added to an alkyne following which rule?

23. The initial step in the sulfonation of benzene involves the attack of the electrophile on the -cloud of benzene, forming an intermediate known as a:

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

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

26. What is the molecular formula for Cyclopentene?

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

28. 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:

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

30. 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?

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

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

3. If 1-Chloropropane is used in the Wurtz reaction, what is the structure of the major alkane product formed?

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

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

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

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

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

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

10. 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:

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

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

13. The process of heating higher alkanes in the absence of air and often in the presence of a catalyst to break them into smaller, lower molecular mass hydrocarbons (alkanes and alkenes) is called:

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

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

16. 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?

17. What is the molecular formula for -Hexane?

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

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

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

21. According to Hückel's rule, for a compound to be considered aromatic, the number of electrons in the fully conjugated cyclic system must satisfy which formula?

22. The electrophile that attacks the benzene ring during the nitration reaction is:

23. The reaction of Ethyne with hydrogen gas () in the presence of Nickel () catalyst yields which final product?

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

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

26. 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?

27. What is the correct name for the compound ?

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

29. When the product of a Friedel–Crafts acylation () is treated with and concentrated (Clemmensen Reduction), the final product obtained is a:

30. The intermediate formed by the reaction of the electrophile () and the benzene ring is known as the complex. This intermediate is stabilized by:

31. The electrophilic substitution reactions are characteristic of aromatic compounds because:

32. How many total structural isomers (including chain and position) are possible for the molecular formula ? (Exclude geometrical isomers).

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

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

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

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

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

38. What is the correct IUPAC name for the alkane structure ?

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

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

41. What is the necessary condition or reagent (Z) to carry out the following transformation from Chlorobenzene to Benzene?

42. According to Hückel's Rule, which of the following -electron counts is characteristic of an anti-aromatic compound?

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

44. The conversion of a vicinal dihalide () to an alkene requires treatment with:

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

46. 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?

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

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

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

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