JEE Main - Common reaction types substitution addition elimination and rearrangement Online Test (MCQ Quiz)

1. Which type of reaction involves the breaking of a pi bond and the formation of two new sigma bonds?

A) Substitution B) Addition C) Elimination D) Rearrangement

2. In an elimination reaction, what is typically removed from a molecule?

A) An atom or group from a single carbon B) Two atoms or groups from adjacent carbons C) An atom or group from a single carbon and a hydrogen from an adjacent carbon D) Atoms or groups from non-adjacent carbons

3. Which of the following is a classic example of a nucleophilic substitution reaction?

A) Ethene reacting with HBr B) Cyclohexane undergoing free radical chlorination C) Ethyl bromide reacting with hydroxide ion D) But-1-ene reacting with H2O in the presence of acid

4. A rearrangement reaction is characterized by:

A) The formation of a double or triple bond B) The replacement of one atom or group by another C) A change in the carbon skeleton of the molecule D) The addition of atoms across a multiple bond

5. Which mechanism is most commonly associated with SN2 reactions?

A) Carbocation intermediate B) Carbanion intermediate C) Concerted, single-step process D) Free radical intermediate

6. The reaction of an alkene with a halogen (e.g., Br2) in the absence of a solvent is an example of:

A) Substitution B) Addition C) Elimination D) Rearrangement

7. Which of the following conditions favors elimination reactions over substitution reactions?

A) Primary alkyl halide and a strong nucleophile B) Secondary or tertiary alkyl halide and a strong, bulky base C) Primary alkyl halide and a weak nucleophile D) Secondary or tertiary alkyl halide and a mild temperature

8. A carbocation intermediate is typically formed in which type of substitution reaction?

A) SN1 B) SN2 C) SNi D) All of the above

9. The conversion of an alkane to an alkene by removing two hydrogen atoms is an example of:

A) Addition B) Substitution C) Dehydrogenation (a type of elimination) D) Rearrangement

10. Which reaction involves the migration of an alkyl or aryl group from one atom to another within the same molecule?

A) Addition B) Substitution C) Elimination D) Rearrangement

11. The addition of H2O to an alkene in the presence of an acid catalyst follows which rule for regioselectivity?

A) Zaitsev's Rule B) Hofmann's Rule C) Markovnikov's Rule D) Kharasch Effect

12. Which type of reaction is represented by the conversion of 2-bromopropane to propene?

A) Substitution B) Addition C) Elimination D) Rearrangement

13. The reaction of an alcohol with a strong acid (like H2SO4) at high temperature to form an alkene is an example of:

A) Substitution B) Addition C) Elimination D) Rearrangement

14. In a free radical substitution reaction, which species initiates the chain mechanism?

A) Nucleophile B) Electrophile C) Free radical D) Carbocation

15. The Walden inversion is a characteristic feature of which substitution reaction?

A) SN1 B) SN2 C) SNi D) Electrophilic addition

16. Which of the following is NOT a common type of rearrangement reaction?

A) Pinacol rearrangement B) Claisen rearrangement C) Diels-Alder reaction D) Beckmann rearrangement

17. The addition of a halogen to an alkyne typically occurs in how many steps?

A) One step, forming a dihalide B) Two steps, forming a tetrahalide C) One step, forming a tetrahalide D) Two steps, forming a dihalide

18. The reaction of an alkyl halide with a strong base like KOH in ethanol at reflux temperature primarily leads to:

A) Substitution B) Addition C) Elimination D) Rearrangement

19. Which of the following is a characteristic of SN1 reactions?

A) First-order kinetics B) Inversion of configuration C) Concerted mechanism D) Favored by primary alkyl halides

20. The reaction where a nucleophile replaces a leaving group on a saturated carbon atom is called:

A) Addition B) Elimination C) Substitution D) Rearrangement

21. Electrophilic addition to alkenes typically involves:

A) Formation of a carbocation intermediate B) A concerted mechanism C) Formation of a carbanion intermediate D) Free radical initiation

22. Dehydrohalogenation of alkyl halides is a type of:

A) Substitution B) Addition C) Elimination D) Rearrangement

23. Which of the following reactions is an example of a rearrangement?

A) CH3CH2Br + NaOH -> CH3CH2OH + NaBr B) CH2=CH2 + Br2 -> CH2BrCH2Br C) CH3CH2OH + H2SO4 (heat) -> CH2=CH2 + H2O D) The conversion of 2-methyl-2-butanol to 2-methyl-1-butene under acidic conditions

24. The rate of an SN2 reaction is dependent on the concentration of:

A) Alkyl halide only B) Nucleophile only C) Alkyl halide and nucleophile D) Solvent only

25. What is the primary product when ethene reacts with HBr?

A) 1-bromoethane B) 2-bromoethane C) Dibromoethane D) Ethanol

26. Which type of reaction leads to the formation of a more unsaturated compound from a less unsaturated one?

A) Substitution B) Addition C) Elimination D) Rearrangement

27. The reaction of a tertiary alkyl halide with a weak nucleophile in a protic solvent will likely proceed via:

A) SN1 mechanism B) SN2 mechanism C) E1 mechanism D) E2 mechanism

28. Which rearrangement reaction involves the conversion of a ketone to an amide in the presence of sulfuric acid?

A) Pinacol rearrangement B) Claisen rearrangement C) Beckmann rearrangement D) Favorskii rearrangement

29. The addition of Br2 to cyclohexene results in:

A) Syn addition B) Anti addition C) Rearrangement D) Elimination

30. What is the driving force for many elimination reactions?

A) Formation of a stable carbocation B) Formation of a more stable alkene C) Nucleophilic attack D) Rearrangement of the carbon skeleton

31. Which of the following is an example of nucleophilic addition?

A) Reaction of an alkene with H2 B) Reaction of a ketone with HCN C) Reaction of an alkyl halide with KCN D) Reaction of an alkane with Cl2 under UV light

32. An E2 reaction requires:

A) A strong nucleophile and a strong base B) A strong base and a specific stereochemical orientation C) A weak base and a protic solvent D) A carbocation intermediate

33. The reaction of an alkene with KMnO4 under mild conditions (Baeyer's test) is an example of:

A) Substitution B) Addition C) Oxidation (a type of addition) D) Elimination

34. Which of the following is a characteristic of SN2 reactions?

A) Racemization B) Inversion of configuration C) Formation of a carbocation D) Favored by polar protic solvents

35. The reaction of ethene with water in the presence of sulfuric acid is an example of:

A) Substitution B) Addition C) Elimination D) Rearrangement

36. Which reaction type is primarily responsible for the synthesis of alkenes from alcohols?

A) Substitution B) Addition C) Elimination D) Rearrangement

37. The pinacol rearrangement involves the acid-catalyzed rearrangement of:

A) Epoxides B) 1,2-diols C) 1,3-diketones D) Aldehydes

38. Which of the following is an example of electrophilic substitution?

A) Benzene reacting with Br2 in the presence of FeBr3 B) Ethene reacting with HBr C) Propene reacting with H2O D) 2-bromopropane reacting with KOH

39. The reaction of a primary alkyl halide with sodium ethoxide in ethanol can lead to both substitution and elimination. Which condition favors elimination?

A) Low temperature B) Dilute solution C) High temperature and a more concentrated solution D) A protic solvent

40. Which of the following is a characteristic of E1 reactions?

A) First-order kinetics B) Concerted mechanism C) Favored by strong bases D) Syn elimination

41. The addition of a hydrogen halide to an unsymmetrical alkene follows Markovnikov's rule, meaning the hydrogen atom adds to:

A) The carbon with fewer hydrogen atoms B) The carbon with more hydrogen atoms C) The carbon involved in the double bond D) The carbon with the most electronegative substituent

42. Which reaction involves the simultaneous removal of a leaving group and a proton from adjacent carbons?

A) SN1 B) SN2 C) E1 D) E2

43. The reaction of an aldehyde or ketone with a Grignard reagent is an example of:

A) Substitution B) Addition C) Elimination D) Rearrangement

44. A molecular rearrangement where a carbocation loses a proton is characteristic of which reaction type?

A) SN1 B) SN2 C) E1 D) E2

45. The reaction of an alkene with ozone followed by a reducing agent (ozonolysis) is a type of:

A) Addition B) Substitution C) Elimination D) Rearrangement

46. What is the main product when tert-butyl bromide reacts with sodium hydroxide in aqueous solution?

A) 2-methylpropene B) tert-butyl alcohol C) 1-bromo-2-methylpropane D) Propane

47. Which reaction type involves the formation of a new sigma bond by breaking a pi bond?

A) Substitution B) Addition C) Elimination D) Rearrangement

48. The Fiest-Benary furan synthesis is an example of a reaction that involves:

A) Substitution and elimination B) Addition and rearrangement C) Cyclization and elimination D) Double substitution

49. In the reaction of an alkyl halide with alcoholic KOH, the major product is usually the most substituted alkene according to:

A) Markovnikov's Rule B) Hofmann's Rule C) Zaitsev's Rule D) Kharasch Effect

50. Which of the following is a characteristic of addition reactions to alkenes?

A) Saturation of the molecule B) Formation of pi bonds C) Increase in the number of sigma bonds D) Loss of atoms from the molecule

Common reaction types substitution addition elimination and rearrangement - Online Test

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