TRB PG Assistant - Functional group interconversions, common reagents and catalysts for organic transformations Question Bank with Options

1. Which reagent is used for the conversion of an alkyne to a trans-alkene?

A) Sodium (Na) in liquid ammonia (NH3)

B) Hydrogen (H2) with Lindlar's catalyst

C) Hydrogen (H2) with Pd/C

D) Borane (BH3) followed by H2O2/NaOH

2. What is the product of the reaction between an ester and a Grignard reagent (excess)?

A) A tertiary alcohol

B) A secondary alcohol

C) A primary alcohol

D) A ketone

3. The Wolff-Kishner reduction is used to convert carbonyl groups to methylene groups. What are the key reagents?

A) Hydrazine (N2H4) and a strong base (e.g., KOH)

B) Lithium aluminum hydride (LiAlH4)

C) Sodium borohydride (NaBH4)

D) Hydrogen and Pd/C

4. Which reagent is commonly used to convert a primary alcohol to a secondary alkyl halide through a SN1 mechanism, if applicable?

A) Concentrated HBr or HCl

B) SOCl2

C) PBr3

D) LiAlH4

5. What is the role of osmium tetroxide (OsO4) in the Upjohn dihydroxylation?

A) To oxidize alcohols to aldehydes

B) To cleave carbon-carbon double bonds

C) To add two hydroxyl groups across a double bond syn-addition

D) To convert alkenes to epoxides

6. Which reagent is used for the conversion of a phenol to an ether?

A) Alkyl halide in the presence of a base (Williamson ether synthesis)

B) Lithium aluminum hydride (LiAlH4)

C) Sodium borohydride (NaBH4)

D) Thionyl chloride (SOCl2)

7. What is the purpose of using copper(I) cyanide (CuCN) in the Rosenmund-von Braun reaction?

A) To replace a diazonium group with a nitrile group

B) To replace an alkyl halide with a nitrile group

C) To reduce a carboxylic acid

D) To oxidize an aldehyde

8. Which catalyst is often used in the hydrogenation of alkynes to alkanes?

A) Platinum (Pt)

B) Lindlar's catalyst

C) Sodium in liquid ammonia

D) Pd/C

9. What is the product of the reaction between an alcohol and sodium metal (Na)?

A) An alkoxide and hydrogen gas

B) An ether

C) An ester

D) A carboxylic acid

10. Which reagent is used to convert a primary alcohol to a bromide via SN2 reaction?

A) PBr3

B) SOCl2

C) H2SO4

D) LiAlH4

11. The conversion of an alkene to an alkyl halide is an electrophilic addition reaction. What is the general reagent used?

A) HX (where X is a halogen)

B) H2/Pd

C) O3

D) KMnO4

12. What is the primary role of a reducing agent like DIBAL-H (Diisobutylaluminium hydride) at low temperatures?

A) Complete reduction of esters to primary alcohols

B) Partial reduction of esters to aldehydes

C) Oxidation of aldehydes to carboxylic acids

D) Reduction of amides to amines

13. Which reagent is used to convert an alkyl halide to a tertiary alcohol via a two-step process involving Grignard formation and reaction with a ketone?

A) Magnesium metal (Mg) followed by a ketone and acid workup

B) Lithium aluminum hydride (LiAlH4)

C) Sodium borohydride (NaBH4)

D) Thionyl chloride (SOCl2)

14. What is the purpose of using a Lewis acid catalyst like AlCl3 in the Friedel-Crafts acylation reaction?

A) To activate the acyl halide and generate an electrophile

B) To reduce the acyl halide

C) To oxidize the aromatic ring

D) To remove a proton from the aromatic ring

15. Which catalyst is used in the catalytic hydrogenation of nitroarenes to anilines?

A) Pd/C (Palladium on carbon)

B) AlCl3

C) Zn/HCl

D) SOCl2

16. What is the product of the reaction between an aldehyde and HCN followed by hydrolysis?

A) An alpha-hydroxy carboxylic acid (cyanohydrin)

B) An ester

C) An alkane

D) An alcohol

17. Which reagent is used for the conversion of an alkene to an alkane with anti-Markovnikov addition of HBr?

A) HBr in the presence of peroxides

B) HBr alone

C) Br2/H2O

D) H2/Pd

18. What is the function of sodium ethoxide (NaOEt) in the synthesis of ethyl acetate from ethanol and acetic acid?

A) It acts as a catalyst for esterification.

B) It acts as a base to deprotonate ethanol.

C) It acts as a solvent.

D) It acts as a dehydrating agent.

19. The Baeyer-Villiger oxidation converts ketones into esters. What is the typical oxidizing agent?

A) Peroxy acids (e.g., m-CPBA)

B) Potassium permanganate (KMnO4)

C) Chromic acid

D) Ozone (O3)

20. Which reagent is used to convert a carboxylic acid to a primary amine with one less carbon atom (via Curtius rearrangement)?

A) Sodium azide (NaN3) and heat

B) Thionyl chloride (SOCl2)

C) Lithium aluminum hydride (LiAlH4)

D) Grignard reagent (RMgX)

21. What is the primary use of dicyclohexylcarbodiimide (DCC) in organic synthesis?

A) Reduction of carbonyl compounds

B) Oxidation of alcohols

C) Formation of amide and ester bonds

D) Halogenation of alkanes

22. Which catalyst is commonly used in the Friedel-Crafts alkylation reaction?

A) Aluminum chloride (AlCl3)

B) Palladium on carbon (Pd/C)

C) Raney Nickel

D) Sodium metal (Na)

23. What is the product of the reaction between an ester and LiAlH4 followed by aqueous workup?

A) A primary alcohol

B) A secondary alcohol

C) A tertiary alcohol

D) An aldehyde

24. Which reaction is used to convert an alkyl halide into a nitrile?

A) Reaction with sodium cyanide (NaCN)

B) Reaction with potassium permanganate (KMnO4)

C) Reaction with lithium aluminum hydride (LiAlH4)

D) Reaction with bromine (Br2)

25. What is the purpose of using a dehydrating agent like P2O5 or concentrated H2SO4?

A) To add water to a molecule

B) To remove water from a molecule

C) To oxidize a molecule

D) To reduce a molecule

26. The conversion of an alkene to an epoxide is typically achieved using which reagent?

A) m-CPBA (meta-Chloroperoxybenzoic acid)

B) Ozone (O3)

C) Potassium permanganate (KMnO4)

D) Bromine (Br2)

27. Which of the following reagents can convert an amide to an amine?

A) LiAlH4

B) NaBH4

C) H2/Pd

D) SOCl2

28. What is the function of Raney Nickel in hydrogenation reactions?

A) To selectively reduce alkynes to cis-alkenes

B) To catalyze the addition of hydrogen to unsaturated compounds

C) To oxidize alcohols to aldehydes

D) To dehalogenate alkyl halides

29. The Oppenauer oxidation is a selective oxidation of secondary alcohols to ketones. What is the oxidizing agent typically used?

A) Aluminum isopropoxide in the presence of acetone

B) Potassium dichromate

C) Chromic acid

D) Permanganate

30. Which reagent is commonly used for the conversion of a primary amine to a diazonium salt?

A) NaNO2/HCl

B) HNO3

C) H2SO4

D) PCl5

31. What is the product of the reaction between a ketone and a Grignard reagent (RMgX) followed by acidic workup?

A) A primary alcohol

B) A secondary alcohol

C) A tertiary alcohol

D) An alkane

32. The Hell-Volhard-Zelinsky (HVZ) reaction involves the alpha-halogenation of carboxylic acids. What is the typical reagent used?

A) Br2/PBr3

B) Cl2/SOCl2

C) I2/KI

D) F2/HF

33. Which reagent is used to convert a terminal alkyne into a terminal alkene (cis-alkene)?

A) H2/Pd

B) Na/NH3 (liquid)

C) H2/Lindlar's catalyst

D) BH3 followed by H2O2/NaOH

34. What is the purpose of using a protecting group for alcohols in multi-step synthesis?

A) To increase the reactivity of the alcohol

B) To prevent the alcohol from reacting during other transformations

C) To convert the alcohol into an alkene

D) To catalyze the reaction

35. The Wittig reaction is used to synthesize alkenes from carbonyl compounds. What are the key reactants involved?

A) Aldehyde/ketone and a phosphonium ylide

B) Carboxylic acid and an alcohol

C) Alkyl halide and a strong base

D) Alkene and a peroxy acid

36. Which reagent is used to convert an ester to a carboxylic acid and an alcohol?

A) Acid hydrolysis (e.g., H2SO4/H2O)

B) Base hydrolysis (saponification, e.g., NaOH/H2O)

C) Reduction with LiAlH4

D) Reaction with Grignard reagent

37. What is the primary role of PCC (Pyridinium chlorochromate) in organic chemistry?

A) Oxidation of primary alcohols to carboxylic acids

B) Oxidation of primary alcohols to aldehydes

C) Reduction of ketones to secondary alcohols

D) Conversion of alcohols to alkyl chlorides

38. The Sandmeyer reaction is used to replace a diazonium group with various substituents. What are the typical reagents used in this reaction?

A) CuX (where X = Cl, Br, CN)

B) H2/Pd

C) LiAlH4

D) SOCl2

39. Which reagent is used to convert an alkene to a vicinal diol (glycol)?

A) Osmium tetroxide (OsO4) followed by a reducing agent

B) Bromine (Br2) in water

C) Ozone (O3)

D) Potassium permanganate (KMnO4) under neutral or basic conditions

40. What is the product of the reaction between an aldehyde and a Grignard reagent (RMgX) followed by acidic workup?

A) A primary alcohol

B) A secondary alcohol

C) A tertiary alcohol

D) A ketone

41. The conversion of an alkyl halide to an alkene is known as dehydrohalogenation. Which strong base is commonly used for this transformation?

A) Sodium hydroxide (NaOH)

B) Potassium tert-butoxide (KOtBu)

C) Ethanol (EtOH)

D) Water (H2O)

42. Which reagent is used for the ozonolysis of alkenes to cleave the carbon-carbon double bond and form carbonyl compounds?

A) H2/Ni

B) O3 followed by a reductive workup (e.g., Zn/H2O)

C) Br2

D) H2SO4

43. What is the main purpose of using lithium aluminum hydride (LiAlH4) in organic synthesis?

A) Selective reduction of esters to primary alcohols

B) Selective reduction of aldehydes to primary alcohols

C) Reduction of amides to amines

D) All of the above

44. Fischer esterification is a reaction that converts a carboxylic acid and an alcohol into an ester. What is the typical catalyst used in this reaction?

A) Concentrated sulfuric acid (H2SO4)

B) Sodium hydroxide (NaOH)

C) Hydrochloric acid (HCl)

D) Ammonia (NH3)

45. Which reagent can be used to convert a primary alcohol to a carboxylic acid?

A) PCC (Pyridinium chlorochromate)

B) KMnO4 (Potassium permanganate) under acidic conditions

C) DIBAL-H (Diisobutylaluminium hydride)

D) OsO4 (Osmium tetroxide)

46. What is the role of Lindlar's catalyst in the reduction of alkynes?

A) Complete reduction to alkanes

B) Partial reduction to cis-alkenes

C) Partial reduction to trans-alkenes

D) Oxidation to ketones

47. The conversion of an alkene to an alkane is typically achieved using which reagent combination?

A) H2/Pd

B) O3 followed by Zn/H2O

C) Br2/H2O

D) KMnO4

48. Which catalyst is essential for the Wurtz reaction, used to form carbon-carbon bonds?

A) Palladium (Pd)

B) Platinum (Pt)

C) Sodium metal (Na)

D) Nickel (Ni)

49. What is the primary function of sodium borohydride (NaBH4) in organic synthesis?

A) Oxidation of alcohols to aldehydes

B) Reduction of aldehydes and ketones to alcohols

C) Halogenation of alkanes

D) Dehydration of alcohols

50. Which reagent is commonly used for the conversion of a carboxylic acid to an acid chloride?

A) Thionyl chloride (SOCl2)

B) Sodium borohydride (NaBH4)

C) Grignard reagent (RMgX)

D) Lithium aluminum hydride (LiAlH4)

Functional group interconversions, common reagents and catalysts for organic transformations - Question Bank