Organic halogen compounds preparation properties substitution mechanisms - Question Bank

1. Which of the following statements about SN2 reactions is INCORRECT?
A) They are favored by polar protic solvents.
B) They involve backside attack by the nucleophile.
C) The rate depends on the concentration of both the substrate and the nucleophile.
D) They proceed with inversion of configuration.
2. The addition of HBr to propene in the presence of peroxides follows:
A) Markovnikov's rule
B) Anti-Markovnikov's rule
C) Zaitsev's rule
D) Hofmann's rule
3. The product of the reaction between 1,1-dichloroethane and aqueous KOH is:
A) Ethanol
B) Acetaldehyde
C) Ethane
D) Ethene
4. Carbylamine reaction is used to test for the presence of:
A) Primary amines
B) Secondary amines
C) Tertiary amines
D) Primary, secondary, and tertiary amines
5. Which reagent is used to convert primary alcohols to primary alkyl chlorides?
A) PCl3
B) PCl5
C) SOCl2
D) All of the above
6. The reaction of ethyl iodide with silver acetate yields:
A) Ethyl acetate
B) Ethanol
C) Ethane
D) Diethyl ether
7. Which of the following is a characteristic of SN1 reactions?
A) Involves a bimolecular rate-determining step
B) Favored by strong nucleophiles
C) Proceeds via a carbocation intermediate
D) No rearrangement of carbocation occurs
8. The reaction of chlorobenzene with sodium hydroxide in the presence of cuprous oxide at high temperature and pressure yields:
A) Phenol
B) Aniline
C) Benzaldehyde
D) Benzyl alcohol
9. The relative order of reactivity of alkyl halides towards SN2 reactions is:
A) Primary > Secondary > Tertiary
B) Tertiary > Secondary > Primary
C) Secondary > Primary > Tertiary
D) Primary > Tertiary > Secondary
10. Which of the following is a method for preparing alkyl bromides from alcohols?
A) Reaction with SOBr2
B) Reaction with PBr3
C) Reaction with HBr
D) All of the above
11. The SN2 reaction proceeds with:
A) Racemization
B) Inversion of configuration
C) Retention of configuration
D) Partial racemization and partial inversion
12. Which of the following is an example of an aryl halide?
A) Benzyl chloride
B) Allyl chloride
C) Chlorobenzene
D) Vinyl chloride
13. The reaction of an alkyl halide with magnesium in dry ether produces:
A) Grignard reagent
B) Alkane
C) Alkene
D) Alcohol
14. Which of the following is the most important factor determining the reactivity of an alkyl halide in nucleophilic substitution?
A) The strength of the C-X bond
B) The size of the leaving group
C) The nature of the nucleophile
D) The solvent used
15. The product of the reaction of chloroform with alcoholic KOH and heating is:
A) Benzaldehyde
B) Phenol
C) Carbonyl chloride
D) Formate ester
16. Which of the following conditions favors SN1 reactions over SN2 reactions?
A) Primary alkyl halide, strong nucleophile
B) Tertiary alkyl halide, polar aprotic solvent
C) Primary alkyl halide, polar protic solvent
D) Tertiary alkyl halide, strong nucleophile
17. The Hoffman bromination reaction is used to convert an amide into:
A) An amine with one carbon less
B) An amine with the same number of carbons
C) An amine with one carbon more
D) A nitrile
18. Which mechanism involves a concerted, one-step process?
A) SN1
B) SN2
C) E1
D) E2
19. The conversion of aryl halides to phenols is carried out by:
A) Reaction with NaOH under high pressure and temperature
B) Reaction with alcoholic KOH
C) Reaction with aqueous ammonia
D) Reaction with dilute HCl
20. Which of the following is an example of a vicinal dihalide?
A) 1,1-Dichloroethane
B) 1,2-Dichloroethane
C) 1,3-Dichloropropane
D) 2,2-Dichloropropane
21. The rate of SN2 reaction is increased by:
A) Increasing the steric hindrance around the carbon atom
B) Using a polar protic solvent
C) Using a good leaving group
D) Using a weak nucleophile
22. When an alkyl halide reacts with silver nitrite (AgNO2), the main product is:
A) Nitroalkane
B) Alkyl nitrite
C) Alkane
D) Alkene
23. Which of the following is a benzylic halide?
A) CH3CH2Cl
B) CH3CHClCH3
C) C6H5CH2Cl
D) C6H5Cl
24. The Wurtz reaction involves the reaction of:
A) An alkyl halide with sodium metal
B) An aryl halide with sodium metal
C) An alkyl halide with magnesium
D) An aryl halide with magnesium
25. Which type of halide is least reactive towards nucleophilic substitution?
A) Primary alkyl halide
B) Secondary alkyl halide
C) Tertiary alkyl halide
D) Vinyl halide
26. The reaction of an alkyl halide with ammonia typically leads to:
A) A primary amine
B) A secondary amine
C) A tertiary amine
D) A mixture of amines
27. Which of the following reagents can convert phenol to chlorobenzene?
A) SOCl2
B) PCl5
C) POCl3
D) All of the above
28. In the SN1 mechanism, the rate-determining step is the:
A) Attack of the nucleophile
B) Formation of the carbocation
C) Loss of the leaving group
D) Protonation of the substrate
29. Which of the following is NOT a method for preparing alkyl halides?
A) Halogenation of alkanes
B) Reaction of alcohols with HX
C) Reaction of alcohols with PCl5
D) Hydrolysis of esters
30. The reaction of a vicinal dihalide with zinc dust produces:
A) Alkyne
B) Alkene
C) Alkyl halide
D) Alcohol
31. The Gattermann reaction is similar to the Sandmeyer reaction but uses:
A) Cupric cyanide
B) Copper powder and HCl
C) Cuprous cyanide
D) HCN and copper powder
32. Which of the following alkyl halides will undergo SN1 reaction most readily?
A) 1-Chlorobutane
B) 2-Chlorobutane
C) 2-Chloro-2-methylpropane
D) Chlorobenzene
33. The Williamson ether synthesis involves the reaction of:
A) An alcohol with an acid
B) An alkoxide ion with a primary alkyl halide
C) An alkene with water
D) An alkyl halide with ammonia
34. Which of the following is a characteristic feature of SN2 reactions?
A) Formation of carbocation intermediate
B) Involvement of solvent in the rate-determining step
C) Bimolecular rate-determining step
D) Favored by tertiary alkyl halides
35. What is the product when bromoethane reacts with sodium hydroxide solution?
A) Ethanol
B) Ethene
C) Diethyl ether
D) Ethane
36. The reaction of an alkyl halide with alcoholic KOH leads to:
A) Substitution
B) Elimination
C) Addition
D) Rearrangement
37. Which of the following is the most stable carbocation intermediate in SN1 reactions?
A) Primary carbocation
B) Secondary carbocation
C) Tertiary carbocation
D) Methyl carbocation
38. The Dow process is used for the preparation of:
A) Chlorobenzene from benzene
B) Phenol from chlorobenzene
C) Aniline from chlorobenzene
D) Bromobenzene from benzene
39. Which of the following solvents favors SN1 reactions?
A) Polar aprotic solvents (e.g., acetone, DMSO)
B) Polar protic solvents (e.g., water, ethanol)
C) Nonpolar solvents (e.g., hexane, benzene)
D) Aprotic solvents (e.g., diethyl ether)
40. The Sandmeyer reaction is used to introduce which functional group onto an aromatic ring?
A) Hydroxyl (-OH)
B) Cyano (-CN)
C) Halogen (-Cl, -Br)
D) Amino (-NH2)
41. Which of the following is an example of an allylic halide?
A) CH3Br
B) CH3CH2Cl
C) CH2=CH-CH2Br
D) C6H5Br
42. The rate of SN1 reactions depends on:
A) Concentration of alkyl halide only
B) Concentration of nucleophile only
C) Concentration of both alkyl halide and nucleophile
D) Concentration of solvent and alkyl halide
43. Which of the following is the most reactive alkyl halide towards SN2 reactions?
A) Primary alkyl halide
B) Secondary alkyl halide
C) Tertiary alkyl halide
D) Vinyl halide
44. In SN2 reactions, the nucleophile attacks from the backside, leading to:
A) Retention of configuration
B) Racemization
C) Inversion of configuration
D) Epimerization
45. Which of the following is a characteristic reaction of alkyl halides?
A) Electrophilic substitution
B) Nucleophilic substitution
C) Addition reactions
D) Rearrangement reactions
46. The reaction of an alkene with HBr in the presence of peroxides follows which rule?
A) Markovnikov's rule
B) Anti-Markovnikov's rule (Peroxide effect)
C) Zaitsev's rule
D) Hofmann's rule
47. Finkelstein reaction is used to prepare alkyl iodides from alkyl chlorides or bromides using which reagent?
A) Sodium iodide in acetone
B) Sodium bromide in acetone
C) Sodium chloride in acetone
D) Sodium fluoride in acetone
48. Which reagent is commonly used to convert a carboxylic acid into an acyl chloride?
A) SOCl2
B) PCl5
C) PCl3
D) All of the above
49. The reaction of an alkyl halide with sodium ethoxide in ethanol is an example of which type of reaction?
A) Nucleophilic substitution (SN1)
B) Nucleophilic substitution (SN2)
C) Elimination (E1)
D) Elimination (E2)
50. Which of the following is the most common method for the industrial preparation of chlorobenzene?
A) Sandmeyer reaction
B) Gattermann reaction
C) Direct chlorination of benzene
D) Dow process