Alkynes acidic character addition reactions and polymerization - One Line Questions

1. The addition of one mole of HBr to 1-butyne follows Markovnikov's rule and produces: — 2-Bromo-1-butene
2. The addition of H2O to 1-butyne in the presence of HgSO4 and dil. H2SO4 will yield: — 2-Butanone
3. When ethyne reacts with one equivalent of Br2, the product is: — Vinyl bromide
4. The product of the reaction of propyne with NaNH2 followed by CH3I is: — 2-Butyne
5. The acidic hydrogen in ethyne can be replaced by: — All of the above
6. Ozonolysis of 2-butyne followed by workup yields: — Two molecules of acetaldehyde
7. The ozonolysis of propyne followed by reductive workup yields: — Acetaldehyde and formaldehyde
8. The conjugate base of ethyne is called: — Acetylide ion
9. The polymerization of ethyne to polyacetylene is a type of: — Addition polymerization
10. The hydration of an unsymmetrical alkyne like propyne follows Markovnikov's rule, leading to the formation of a(n): — Ketone
11. Which of the following can be synthesized using the alkylation of terminal alkynes? — Internal alkynes
12. Terminal alkynes can react with heavy metal ions like silver (Ag+) and copper(I) (Cu+) to form: — Explosive metal acetylides
13. Hydroboration-oxidation of a terminal alkyne results in the formation of: — An aldehyde
14. Acid-catalyzed hydration of internal alkynes like 2-butyne yields: — A ketone
15. The reaction of ethyne with hot concentrated sulfuric acid leads to: — Benzene
16. The structure of the acetylide ion formed from ethyne is: — HC≡C-
17. Dissolving metal reduction (e.g., Na in liquid NH3) of an alkyne yields: — trans-Alkene
18. The reaction where an alkyne is converted to a cis-alkene using a poisoned palladium catalyst is known as: — Lindlar reduction
19. The reaction of ethyne with dilute H2SO4 and HgSO4 is an example of: — Electrophilic addition
20. Which of the following is a characteristic reaction of terminal alkynes that distinguishes them from internal alkynes? — Formation of metal acetylides with Ag+ or Cu+
21. Which of the following reactions demonstrates the acidic character of alkynes? — Reaction with sodium amide in liquid ammonia
22. The reaction of a terminal alkyne with a strong base like NaNH2 followed by an alkyl halide (R-X) is an example of: — Nucleophilic substitution (alkylation)
23. The reaction of ethyne with hydrogen gas in the presence of a catalyst like Pd/BaSO4 (Lindlar's catalyst) produces: — Ethene
24. Addition of H2O to ethyne in the presence of HgSO4 and dil. H2SO4 yields: — Acetaldehyde
25. Which of the following is the most acidic alkyne? — Ethyne
26. The rate of deprotonation of alkynes with a base increases in the order: — Ethyne > Propyne > 1-Butyne
27. Which statement is FALSE regarding the acidic character of alkynes? — Acidity decreases with increasing s-character of the hybrid orbital.
28. Ozonolysis of ethyne followed by reductive workup yields: — Glyoxal
29. The anti-Markovnikov addition of water to alkynes is achieved by: — BH3 followed by H2O2/OH-
30. Which of the following is a consequence of the sp hybridization of carbon atoms in alkynes? — Increased acidity
31. The formation of a precipitate with ammoniacal silver nitrate solution is a test for: — Terminal alkynes
32. Which of the following is a property of the sp hybridized carbon atom in alkynes? — It has 50% s-character.
33. The polymerization of alkynes can be catalyzed by: — All of the above
34. Which catalyst is used for the complete reduction of alkynes to alkanes? — Raney Nickel or Pt/Pd
35. The conversion of an alkyne to a trans-alkene can be achieved by using: — Na in liquid NH3
36. Which of the following conditions favors polymerization of alkynes? — High temperature and presence of catalysts
37. The addition of halogens (e.g., Br2) to alkynes follows: — Anti-addition mechanism
38. The reaction of ethyne with dilute nitric acid and mercuric nitrate yields: — Nitroacetylene
39. Reaction of acetylene with hot concentrated nitric acid results in the formation of: — Benzene
40. Which of the following terminal alkynes is the most acidic? — Ethyne
41. Polymerization of ethyne leads to the formation of: — Polyacetylene
42. Which catalyst is used for the partial reduction of alkynes to cis-alkenes? — Lindlar's catalyst
43. Which type of bond is broken during the addition of HBr to ethyne? — Pi bond
44. Which reagent is commonly used to deprotonate terminal alkynes? — Sodium amide (NaNH2)
45. The acidic nature of terminal alkynes is due to: — The high s-character of the sp hybridized carbon atom
46. The reduction of an alkyne with Na/NH3 (liquid) yields a mixture of cis and trans alkenes. — True, primarily trans alkene is formed.
47. The polymerization of ethyne can produce conjugated polymers with interesting electronic properties. — True, such polymers are called polyalkynes.
48. What is the intermediate formed during the hydration of ethyne before tautomerization? — Vinyl alcohol
49. Which of the following is NOT a product of the addition of HBr to ethyne? — Bromoethane
50. When ethyne reacts with excess HBr, the product formed is: — 1,1-Dibromoethane
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