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

1. Hydrolysis of benzyl chloride, , does not directly give benzaldehyde because the principal product is:

2. Alcohol vapours are commonly passed over heated copper near ______ during catalytic dehydrogenation.

3. Consider the following statements about the carbonyl group.
Statement I: The carbonyl carbon is approximately trigonal planar.
Statement II: The bond contains one sigma and one pi bond.
Statement III: Free rotation about the bond occurs as readily as rotation about a carbon-carbon single bond.

4. The bond most directly responsible for proton donation by a carboxylic acid is:

5. The row that gives the correct sequence for converting toluene into benzaldehyde is:

6. During Clemmensen reduction, the oxidation number of the carbonyl carbon decreases by the same amount for an aldehyde and a ketone. What is this decrease?

7. A graph plots the magnitude of the electron-withdrawing inductive effect of chlorine on the vertical axis against the number of sigma bonds separating chlorine from the carboxyl group on the horizontal axis. Which shape is most appropriate?

8. Bromoethane, , is converted into propanenitrile in yield. Hydrolysis converts of the nitrile into propanoic acid. The acid is then converted into ethyl propanoate, which is isolated in yield. What mass of ester is obtained? Use .

9. A (0.300,mathrm{mol}) mixture of methanal and ethanal has a mass of (11.8,mathrm{g}). One sample is treated with excess Tollens reagent under conditions in which methanal is completely oxidised to carbonate. An identical sample is subjected to the iodoform test. Assume that one mole of methanal deposits four moles of silver, while one mole of ethanal deposits two moles of silver. Which pair gives the theoretical silver mass and iodoform mass? Use (M(mathrm{Ag})=108,mathrm{g,mol^{-1}}) and (M(mathrm{CHI_3})=394,mathrm{g,mol^{-1}}).

10. Ketones generally undergo aldol addition more slowly than comparable aldehydes mainly because ketone carbonyl groups:

11. Assertion: Ethanal undergoes aldol reaction, whereas methanal undergoes Cannizzaro reaction under suitable alkaline conditions.
Reason: Both ethanal and methanal contain alpha hydrogen atoms.

12. The nitrile required to prepare -methylbutanal by Stephen reduction is:

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

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

15. A sample of propene at STP undergoes complete reductive ozonolysis. What is the total amount of carbonyl products formed?

16. 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.

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

18. During nucleophilic addition to a carbonyl compound, the geometry at the carbonyl carbon changes initially from:

19. Match the feature in Column I with its description in Column II.

20. Why is excess ammonia commonly used when an acyl chloride is converted into a primary amide?

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

22. Schiff reagent is best described as:

23. Bromoethane, , is converted into ethylmagnesium bromide with yield. The Grignard reagent is then treated with of carbon dioxide at and , followed by acidic hydrolysis. Propanoic acid is isolated in yield. Which pair gives the limiting reactant in the carbonation step and the isolated acid mass? Use and .

24. Methanoic acid, , is treated with excess Tollens reagent. Exactly of the acid reacts, and the deposited silver is recovered in yield. Which pair gives the recovered silver mass and the unreacted methanoic-acid mass? Use and .

25. A mixture of ethanoyl chloride and ethyl ethanoate is hydrolysed completely. Neutralisation of all acidic products requires of sodium hydroxide. In a separate identical experiment, all chloride formed is precipitated as . Which pair gives the mole percentage of ethanoyl chloride and the mass of ? Use .

26. The row containing only properly named ketones is:

27. 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.

28. A sample containing of ethanol is completely dehydrogenated over heated copper. What volume of hydrogen is produced at STP, taking molar gas volume as ?

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

30. Ethyne is converted into ethanol through ethanal as an intermediate. Which sequence gives the required transformation?

31. The row containing the correct substrate, condition, and major product is:

32. Phenylacetic acid has the structure . Compared with benzoic acid, its carboxyl group:

33. Ethanenitrile labelled with at the nitrile carbon, , is completely hydrolysed. Where is the isotope found in the organic product?

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

35. For the structure , the longest parent chain that contains the aldehyde carbon has:

36. A carbonyl compound is required as a solvent that is completely miscible with water and also dissolves many organic substances. The most suitable choice is:

37. Methanal occupies a special boundary position among aldehydes because it:

38. Acetophenone, , is reduced under Clemmensen conditions using of zinc and of hydrochloric acid. Use

After complete carbonyl reduction, excess zinc reacts with the remaining acid according to

Ethylbenzene is isolated in yield. Which pair gives its mass and the volume of hydrogen evolved at and ? Use .

39. Assertion: Sodium benzoate is often used instead of benzoic acid in aqueous food formulations.
Reason: Sodium benzoate is generally more soluble in water than benzoic acid.

40. Compared with the bond in a typical alcohol, the bond in a carboxylic acid is more readily ionised mainly because:

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

42. Benzene reacts with ethanoic anhydride in the presence of anhydrous . The principal organic product is:

43. The preparation of a carboxylic acid from a Grignard reagent is represented by:

44. Consider the following statements about the formula .
Statement I: It may represent a saturated acyclic aldehyde.
Statement II: It may represent a saturated acyclic ketone when .
Statement III: Every compound with this formula must be an aldehyde or ketone.

45. Which condition most strongly favours chlorination of the side chain of toluene rather than chlorination of the aromatic ring?

46. During hydrolysis of a nitrile under constant heated conditions, three concentration curves are observed. Curve P decreases continuously. Curve Q rises to a maximum and then decreases. Curve R increases gradually and approaches a plateau. What do P, Q, and R most reasonably represent?

47. Ethylmagnesium bromide reacts with , followed by acidic hydrolysis and then complete reduction with . Where is the label in the final product?

48. The structural feature present in aldehydes, ketones, and carboxylic acids is:

49. Ethanal and propanal are mixed under conditions where both self-aldol and crossed-aldol additions are possible. Ignoring stereoisomers, what is the minimum number of constitutionally different beta-hydroxy aldehydes expected from the two self-additions and the two possible donor-acceptor crossed additions?

50. 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.