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

1. The structure of -bromobutyraldehyde is:

2. Match each compound with its common application.

3. Which comparison of carbonyl derivatives is correct?

4. Read the reaction record below and answer the question.
Ozonolysis of an alkene followed by reductive work-up gives methanal and propanone. The propanone fraction is isolated and reduced with sodium borohydride.
Which pair identifies the original alkene and the final reduction product?

5. Propanal vapour occupies at and . In a Tollens test, of the propanal reacts. Metallic silver is recovered with efficiency, and propanoic acid after acidification is recovered in yield. Which pair gives the recovered silver mass and recovered acid mass? Use .

6. For compounds of broadly comparable molar mass, the most reasonable increasing order of boiling point is:

7. Propanal vapour occupies at and . It is oxidised according to

The propanal conversion is , and the propanoic acid is isolated in yield. Which pair gives the isolated acid mass and the volume of oxygen consumed at STP? Use and at STP.

8. The table proposes roles for four carbonyl compounds under ordinary aldol conditions.

Which row is correct?

9. Match each structure in Column I with its IUPAC name in Column II.

10. A sample of propanone reacts with excess . Cyanohydrin formation occurs in yield, and subsequent complete nitrile hydrolysis to -hydroxy--methylpropanoic acid occurs in yield. What mass of the acid, , is obtained?

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

12. The number of saturated acyclic ketone structural isomers having the molecular formula is:

13. Propanoic acid is treated with bromine in the presence of red phosphorus and then hydrolysed. What is the principal organic product?

14. A acetone sample undergoes self-aldol addition, and of the acetone is consumed. Of the beta-hydroxy ketone formed, undergoes dehydration to . The unsaturated ketone is isolated in yield. Which pair gives its isolated mass and the mass of water chemically formed? Use .

15. Use the arrangement described below: two carboxylic acid molecules are positioned head-to-head so that the hydroxyl hydrogen of each molecule points toward the carbonyl oxygen of the other. This arrangement represents:

16. Propanone is subjected to two separate reactions.
Branch P: in dry ether, followed by acidic hydrolysis.
Branch Q: .
Which pair gives the principal products?

17. The following observations are recorded with Tollens reagent.

Which combination contains all the correct rows?

18. For the condensation equilibrium


A solution initially contains carbonyl compound and ammonia derivative, with no product or water. What percentage of the carbonyl compound is converted at equilibrium?

19. Reductive ozonolysis of cyclohexene gives:

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

21. A graph of iodoform mass against initial moles of a pure methyl ketone is linear while iodine and hydroxide are present in excess. At higher ketone amounts, the graph becomes horizontal because iodine is exhausted. Select the interpretation consistent with this graph.

22. Methylmagnesium bromide reacts with , followed by acidic hydrolysis. Where is the isotope located in the product?

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

24. Ethanal, ethanoic acid, and ethyl ethanoate are present together. Which reagent is most suitable for selectively reducing the ethanal carbonyl group under ordinary controlled conditions while leaving the acid and ester largely unchanged?

25. Consider the following statements about cyclic ketones.
Statement I: In a cyclic ketone, the carbonyl carbon forms part of the ring.
Statement II: Cyclohexanone is a cyclic monoketone.
Statement III: Every cyclic ketone is also a methyl ketone.

26. An unknown compound has molecular formula . It forms an orange precipitate with -DNPH, reduces Tollens reagent, and gives no iodoform precipitate. Reduction with produces:

27. The measured values are:

Which order of decreasing acid strength follows from the data?

28. Assertion: Immediate removal of ethanal during oxidation of ethanol can improve the yield of ethanal.
Reason: Ethanal can undergo further oxidation to ethanoic acid if it remains in contact with the oxidising agent.

29. Assertion: Alpha hydrogens of aldehydes and ketones are more acidic than hydrogens of ordinary alkanes.
Reason: The conjugate base formed after alpha-proton removal is resonance stabilised as an enolate ion.

30. Assertion: A simple acyclic ketone carbonyl cannot occupy carbon of its parent chain.
Reason: A ketone carbonyl carbon must be bonded to carbon groups on both sides.

31. A mixture of ethanal and propanone is completely reduced by the Clemmensen method. The resulting mixture of ethane and propane has a mass of . Which pair gives the total gas volume at STP and the volume percentage of ethane? Use at STP.

32. Sodium bicarbonate labelled at its carbon atom is added to benzoic acid, . Where is the label expected after the reaction?

33. Which order best represents the relative rates of nitration under comparable conditions?

34. Benzaldehyde, , is treated with of potassium hydroxide:

After completion, of hydrochloric acid is added. The acid first neutralises excess and then protonates benzoate. Which pair gives the benzoic acid mass formed and the moles of benzoate remaining? Use and .

35. Assertion: Benzene can be converted into benzaldehyde by Gattermann-Koch formylation even though it initially has no side chain.
Reason: The formyl carbon is introduced from carbon monoxide during electrophilic aromatic substitution.

36. Use the graph description below. The horizontal axis represents increasing stability of the enolate ion formed from a carbonyl compound. The vertical axis represents the of its alpha hydrogen. Which trend is expected?

37. An alkyl halide containing carbon atoms undergoes the sequence

The final hydrocarbon contains ______ carbon atoms.

38. The molecular formula cannot represent a ketone because:

39. Assertion: Conversion of an alcohol into a carbonyl compound over heated copper is an oxidation process even though no oxygen atom is added.
Reason: The functional carbon loses hydrogen and its bonding to oxygen increases.

40. Two ethanal molecules are used in an isotope-tracing aldol experiment. Molecule P contains as its carbonyl oxygen and acts only as the electrophilic acceptor. Molecule Q is unlabelled and forms the enolate donor. After protonation of the aldol intermediate, the label is found in:

41. A sample of ethanol is subjected to controlled oxidation. In Step I, of the ethanol is converted into ethanal. In Step II, of that ethanal is oxidised to ethanoic acid. The acid is isolated in yield. Which pair gives the isolated acid mass and the mass of ethanal remaining after Step II?

42. The sequence that converts benzyl alcohol into benzene through benzoic acid is:

43. Which sequence correctly represents the principal stages of the Cannizzaro mechanism?

44. For the equilibrium

a solution initially contains carbonyl compound, hydroxylamine, and water. No oxime is initially present. At equilibrium, of oxime has formed. What is ?

45. The decreasing order of hydrolysis reactivity among common carboxylic-acid derivatives is:

46. 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?

47. Among propanone, butan-2-one, and pentan-3-one, the symmetrical ketones are:

48. Which row correctly classifies all the compounds shown?

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

50. Semicarbazones are particularly useful in identifying aldehydes and ketones because many of them are: