JEE Main - Aldehydes and ketones nucleophilic addition Grignard reagent oxidation and reduction Online Test (MCQ Quiz)

1. Which functional group is characteristic of aldehydes and ketones?

A) Carboxylic acid (-COOH) B) Hydroxyl (-OH) C) Carbonyl (C=O) D) Amino (-NH2)

2. In aldehydes, the carbonyl group is attached to:

A) Two alkyl groups B) One alkyl group and one hydrogen atom C) Two hydrogen atoms D) One alkyl group and one aryl group

3. In ketones, the carbonyl group is attached to:

A) Two alkyl groups B) One alkyl group and one hydrogen atom C) Two hydrogen atoms D) One alkyl group and one aryl group

4. The general formula for aliphatic aldehydes is:

A) R-CHO B) R-CO-R' C) R-COOH D) R-OH

5. The general formula for aliphatic ketones is:

A) R-CHO B) R-CO-R' C) R-COOH D) R-OH

6. Which of the following is the simplest aldehyde?

A) Acetaldehyde B) Formaldehyde C) Acetone D) Propanal

7. Which of the following is the simplest ketone?

A) Acetone B) Propanone C) Butanone D) Acetaldehyde

8. Nucleophilic addition to aldehydes and ketones involves the attack of a nucleophile on which atom?

A) The oxygen atom of the carbonyl group B) The carbon atom of the carbonyl group C) The alpha-carbon atom D) The hydrogen atom attached to the carbonyl carbon (in aldehydes)

9. In the nucleophilic addition reaction of aldehydes and ketones, the carbon atom of the carbonyl group is:

A) Electron-rich B) Electron-deficient (electrophilic) C) Neutral D) Negatively charged

10. Which reagent is commonly used for the nucleophilic addition reaction with aldehydes and ketones to form cyanohydrins?

A) HCN B) Grignard reagent C) NaBH4 D) LiAlH4

11. The reaction of aldehydes and ketones with HCN in the presence of a base forms:

A) Alcohols B) Carboxylic acids C) Cyanohydrins D) Esters

12. Grignard reagents are organometallic compounds with the general formula:

A) R-MgX B) R-Li C) R-Al D) R-Cu

13. Grignard reagents act as which type of species in their reaction with aldehydes and ketones?

A) Electrophiles B) Nucleophiles C) Acids D) Bases

14. Reaction of a Grignard reagent with formaldehyde followed by hydrolysis yields:

A) Primary alcohol B) Secondary alcohol C) Tertiary alcohol D) Aldehyde

15. Reaction of a Grignard reagent with an aldehyde (other than formaldehyde) followed by hydrolysis yields:

A) Primary alcohol B) Secondary alcohol C) Tertiary alcohol D) Ketone

16. Reaction of a Grignard reagent with a ketone followed by hydrolysis yields:

A) Primary alcohol B) Secondary alcohol C) Tertiary alcohol D) Aldehyde

17. Which of the following is a common reducing agent used for aldehydes and ketones?

A) KMnO4 B) CrO3 C) NaBH4 D) HCl

18. Sodium borohydride (NaBH4) reduces aldehydes and ketones to:

A) Alkanes B) Carboxylic acids C) Alcohols D) Esters

19. Lithium aluminum hydride (LiAlH4) is a stronger reducing agent than NaBH4 and also reduces:

A) Esters and carboxylic acids B) Alkanes C) Alkenes D) Aromatic rings

20. Which of the following reagents is used for the oxidation of primary alcohols to aldehydes?

A) PCC (Pyridinium chlorochromate) B) LiAlH4 C) NaBH4 D) Grignard reagent

21. Pyridinium chlorochromate (PCC) is a mild oxidizing agent that selectively oxidizes primary alcohols to:

A) Carboxylic acids B) Aldehydes C) Ketones D) Esters

22. Strong oxidizing agents like KMnO4 or K2Cr2O7 typically oxidize primary alcohols to:

A) Aldehydes B) Ketones C) Carboxylic acids D) Esters

23. Strong oxidizing agents like KMnO4 or K2Cr2O7 typically oxidize secondary alcohols to:

A) Primary alcohols B) Ketones C) Carboxylic acids D) Aldehydes

24. Which reaction is characteristic of aldehydes but not ketones (under mild conditions)?

A) Nucleophilic addition with HCN B) Reaction with Grignard reagents C) Oxidation to carboxylic acids D) Reduction to alcohols

25. The reaction of aldehydes with alcohols in the presence of an acid catalyst forms:

A) Ethers B) Acetals C) Esters D) Hemiacetals

26. Further reaction of hemiacetals with an alcohol in the presence of an acid catalyst yields:

A) Ethers B) Acetals C) Esters D) Aldehydes

27. Which of the following reactions is used to distinguish between aldehydes and ketones?

A) Tollens' test B) Reaction with HCN C) Reaction with Grignard reagent D) Reduction with NaBH4

28. In Tollens' test, aldehydes are oxidized by Tollens' reagent (ammoniacal silver nitrate) to form:

A) A silver mirror B) A red precipitate C) A blue solution D) A yellow precipitate

29. Ketones do not react with Tollens' reagent under normal conditions, hence they are:

A) Oxidized B) Reduced C) Not oxidized D) Dehydrated

30. Fehling's solution is another reagent used to test for:

A) Ketones B) Aldehydes C) Alcohols D) Carboxylic acids

31. A positive Fehling's test results in the formation of a precipitate of:

A) Silver (Ag) B) Copper(I) oxide (Cu2O) C) Copper(II) oxide (CuO) D) Manganese dioxide (MnO2)

32. Which type of aldehydes give a positive test with Fehling's solution?

A) Aliphatic aldehydes B) Aromatic aldehydes C) Both aliphatic and aromatic aldehydes D) Only ketones

33. The reaction of aldehydes and ketones with sodium bisulfite (NaHSO3) forms:

A) Bisulfite adducts B) Alcohols C) Acids D) Esters

34. The bisulfite adducts formed from aldehydes and ketones are generally:

A) Soluble in water B) Insoluble in water C) Gaseous D) Acids

35. Which of the following is a common method for the preparation of aldehydes?

A) Oxidation of primary alcohols with PCC B) Oxidation of secondary alcohols with KMnO4 C) Reduction of carboxylic acids with LiAlH4 D) Reaction of Grignard reagent with ketones

36. Which of the following is a common method for the preparation of ketones?

A) Oxidation of primary alcohols B) Reaction of Grignard reagent with formaldehyde C) Oxidation of secondary alcohols D) Reduction of esters

37. The reaction of an alkene with ozone followed by reductive workup (e.g., Zn/H2O or (CH3)2S) is called ozonolysis and yields:

A) Aldehydes and/or ketones B) Alcohols only C) Carboxylic acids only D) Esters only

38. Which of the following is NOT a product of the reaction between a Grignard reagent and an ester?

A) Ketone B) Tertiary alcohol C) Aldehyde D) Alkane (from the Grignard reagent)

39. When a Grignard reagent reacts with an ester, it typically leads to the formation of:

A) A ketone B) A tertiary alcohol (after reaction with two equivalents of Grignard reagent) C) An aldehyde D) An ester

40. The Wolff-Kishner reduction is used to convert a carbonyl group of aldehydes and ketones into:

A) An alcohol B) An alkene C) An alkane D) A carboxylic acid

41. In Wolff-Kishner reduction, the reaction proceeds via the formation of a hydrazone which is then heated in the presence of a strong base like:

A) KOH B) HCl C) H2SO4 D) NaOH

42. The Clemmensen reduction is another method for reducing the carbonyl group of aldehydes and ketones to an alkane, using:

A) Zinc amalgam and concentrated HCl B) Sodium borohydride C) Lithium aluminum hydride D) Potassium permanganate

43. Which of the following reactions involves the addition of a nucleophile to the carbonyl carbon, followed by elimination of a leaving group?

A) Nucleophilic addition B) Nucleophilic addition-elimination C) Electrophilic addition D) Electrophilic substitution

44. Reactions of aldehydes and ketones with ammonia derivatives like hydroxylamine (NH2OH) or phenylhydrazine (C6H5NHNH2) lead to the formation of:

A) Alcohols B) Oximes and phenylhydrazones respectively C) Carboxylic acids D) Esters

45. The reaction of aldehydes and ketones with semicarbazide forms:

A) Oximes B) Hydrazones C) Semicarbazones D) Acetals

46. Which statement is true regarding the reactivity of aldehydes and ketones towards nucleophilic addition?

A) Ketones are generally more reactive than aldehydes B) Aldehydes are generally more reactive than ketones C) Reactivity is the same for both D) Aromatic aldehydes are more reactive than aliphatic aldehydes

47. Steric hindrance around the carbonyl group generally decreases reactivity towards nucleophilic addition. Which ketone is least sterically hindered?

A) Acetone B) Propanone C) Butanone D) Hexanone

48. The electron-withdrawing effect of substituents on the carbonyl carbon increases its electrophilicity and thus reactivity towards nucleophilic addition. Which aldehyde is most reactive?

A) Formaldehyde B) Acetaldehyde C) Benzaldehyde D) Propionaldehyde

49. The Cannizzaro reaction is a disproportionation reaction observed with aldehydes that do not have an alpha-hydrogen atom. In this reaction, one molecule is oxidized to a carboxylic acid salt, and another is reduced to:

A) An aldehyde B) A ketone C) A primary alcohol D) A secondary alcohol

Aldehydes and ketones nucleophilic addition Grignard reagent oxidation and reduction - Online Test

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