Aldehydes, Ketones and Carboxylic Acids Mock Test – Class 12 Chemistry

1. One mole of benzaldehyde reacts with one mole of acetone under crossed aldol conditions, followed by dehydration. The principal product has the structure:

2. A graph plots of para-substituted benzoic acids on the vertical axis against increasing electron-withdrawing strength of the para substituent on the horizontal axis. Which trend is expected?

3. During reductive ozonolysis, an alkene carbon that originally carries one hydrogen generally becomes:

4. A laboratory note reports that an unknown carbonyl compound produced no visible colour with Schiff reagent after only a few seconds. The conclusion “the compound must be a ketone” is:

5. The row that classifies the given acids consistently is:

6. The catalyst used in Rosenmund reduction is:

7. Benzaldehyde, , is treated with of phenylhydrazine having density and purity :

If the phenylhydrazone is isolated in yield, what mass is obtained? Use and .

8. The compound is named:

9. Match each property in Column I with its most suitable explanation in Column II.

10. A student compares two routes for preparing propanamide.
Route P: Propanoic acid is treated with ammonia, and the salt is heated.
Route Q: Propanoyl chloride is treated with excess ammonia.
The route comparison supported by acyl-derivative reactivity is:

11. A container of is labelled “butyraldehyde.” The label should instead read:

12. Toluene containing specifically at its methyl carbon is converted into benzaldehyde through benzal chloride. The isotope will be located at:

13. Consider the following statements about ketone oxidation.
Statement I: Ordinary ketones generally resist mild oxidation.
Statement II: Strong oxidation may cleave carbon-carbon bonds and form smaller carboxylic acids.
Statement III: Every unsymmetrical ketone always gives one single carboxylic acid as the exclusive product.

14. An unknown compound is either benzaldehyde, propanone, or benzoic acid. The compound gives no reaction with Fehling solution. Which next test provides the most direct useful distinction among the three possibilities?

15. The structure of benzal chloride is:

16. Methanoic acid undergoes the sequence

What is S?

17. Match each aldehyde in Column I with its classification in Column II.

18. Which balanced equation represents the reaction of ethanoyl chloride with ammonia?

19. Consider the sequence:

What is R?

20. The interaction between the hydroxyl oxygen and the carbonyl system in a carboxylic acid involves donation of a lone pair into the adjacent ______ system.

21. Which conversion sequence correctly transforms propanoic acid into ethyl propanoate through an acyl-chloride intermediate?

22. The base-catalysed self-aldol addition of ethanal proceeds through:

23. The systematic name of is:

24. Why is ordinary Kolbe electrolysis of a mixture of sodium ethanoate and sodium propanoate unsuitable for preparing pure propane?

25. Consider the following ketones.
Statement I: contains a methyl-ketone unit.
Statement II: contains a methyl-ketone unit.
Statement III: contains a methyl-ketone unit.
The ketones structurally eligible for the haloform reaction are represented by:

26. The role of anhydrous in Gattermann-Koch formylation is best described as:

27. The oxygen atom of a carbonyl group can act as a basic or nucleophilic site mainly because it:

28. Assertion: Friedel-Crafts acylation is often preferred over Friedel-Crafts alkylation when a rearrangement-free carbon skeleton is required.
Reason: The acylium ion is resonance stabilised and normally does not undergo carbocation rearrangement.

29. A mixture of ethanol and propan--ol is oxidised under controlled conditions and then treated with excess iodine and alkali. The iodoform is recovered in yield, giving . Which pair gives the ethanol mass percentage and the propan--ol mole percentage in the original mixture?

30. Hydroxide attacks benzaldehyde during the Cannizzaro mechanism. Which intermediate is formed immediately before hydride transfer to a second benzaldehyde molecule?

31. Consider the following statements about aldehyde suffixes.
Statement I: The terminal of an alkane name is removed before adding .
Statement II: The terminal is retained in names such as ethanedial.
Statement III: The suffix is used when the aldehyde carbon is not part of a ring parent.

32. Ethanol, , is oxidised using of dichromate ions in excess acid:

Ethanoic acid is isolated in yield. Which pair gives the isolated acid mass and the mass of unreacted ethanol?

33. Which sequence converts ethanol into ethyl ethanoate through a carboxylic-acid and an acyl-chloride intermediate?

34. A claim states that -nitrobenzoic acid and -nitrobenzoic acid must have identical strengths because both contain one nitro group. The best correction is:

35. Consider the following statements about aldehyde nomenclature.
Statement I: The suffix is used for an open-chain aldehyde.
Statement II: The aldehyde carbon is included in the parent-chain carbon count.
Statement III: The suffix is useful when is attached to a ring.

36. A mixture of ethanoic acid and benzoic acid has a mass of . Each acid is converted completely into its ammonium salt and then heated. Ethanamide is recovered in yield and benzamide in yield. Which pair gives the mole percentage of benzoic acid and the combined recovered amide mass?

37. The measured values are:

Which order of decreasing acid strength follows from the data?

38. Which statement about benzaldehyde is most appropriate?

39. The oxygen atom in a carbonyl group is commonly described as approximately -hybridised because:

40. A mixture of ethanal and propanone has a mass of . Under conditions that completely exchange every alpha hydrogen for deuterium, the mass increases by . Assume each exchanged replaced by increases the molar mass by . Ethanal has three alpha hydrogens and propanone has six. What is the mole percentage of propanone in the original mixture?

41. The general ketone notation is . The missing symbol is:

42. A model shows the carbonyl carbon bonded to oxygen and two other atoms. The three sigma bonds lie in one plane, while electron density occurs above and below that plane. The electron density above and below the plane represents:

43. Assertion: Ethanamide hydrolyses much more slowly than ethanoyl chloride under comparable conditions.
Reason: Nitrogen donates electron density into the amide carbonyl by resonance, and the amide-derived leaving group is poorer than chloride.

44. Three compounds are known to be ethanal, propanone, and ethanoic acid. Which test sequence identifies all three with the fewest ambiguous results?

45. Assertion: Heating -hydroxybutanal commonly produces but--enal.
Reason: Dehydration creates a carbon-carbon double bond conjugated with the aldehyde carbonyl group.

46. The alcohol that gives a positive iodoform test because oxidation produces a methyl ketone is:

47. Which product pair is formed when -methylbutan--one, , undergoes the iodoform reaction?

48. Benzene is to be converted into -phenylethanol through an aromatic ketone. Which reagent sequence is appropriate?

49. Two equal carbon-oxygen bond lengths are observed in a carboxylate ion. This equality is best explained by:

50. The row that correctly relates alcohol class to its major product over heated copper is: