Amines Mock Test – Class 12 Chemistry

1. The alkylation step of Gabriel synthesis proceeds mainly through:

2. The conjugate acid of aniline does not receive the same lone-pair resonance stabilisation as neutral aniline because, after protonation:

3. A graph plots the wavelength of maximum absorption, , against the extent of conjugation in a related series of azo compounds. Which broad trend is most reasonable?

4. A compound with structure has been named -aminobutane. When the amine is treated as the principal functional group, the preferred repair is:

5. A sample of benzenediazonium chloride is divided into two portions. Portion P contains of the sample and is coupled with excess phenol; undergoes coupling, and the azo product is isolated in yield. Portion Q is hydrolysed with conversion, and phenol is isolated in yield. Use and . The isolated product masses and the amount of nitrogen evolved are:

6. The pair that represents constitutional isomers differing only in whether methyl is attached to nitrogen or to the aromatic ring is:

7. In propanamide, label the methyl carbon as C1, the methylene carbon as C2, and the carbonyl carbon as C3. After Hoffmann bromamide degradation, which carbon is absent from ethanamine?

8. The IUPAC name of is:

9. The nitrogen–nitrogen bond in an arenediazonium ion has substantial multiple-bond character because:

10. The sulphonamide formed from a primary amine dissolves in excess aqueous alkali because:

11. Examine the reaction records below.

The valid row is:

12. The principal product formed when benzenediazonium chloride couples with phenol in alkaline medium, with the para position of phenol free, is:

13. Use the following passage.
A student mixes aniline, ethanoyl chloride, and anhydrous , expecting ring acylation. Instead, the nitrogen atom binds strongly to the catalyst, and the ring becomes much less reactive.
Which conclusion is most appropriate?

14. A graph shows the fraction of an amine present as against . The graph is described by:

15. A impure sample of ethane--diamine is completely protonated by of hydrochloric acid. The impurity is inert. If the resulting diammonium salt, molar mass , is isolated in yield, the purity of the sample and the salt mass obtained are:

16. Use the following passage.
An unknown amine gives no carbylamine reaction. With benzenesulphonyl chloride, it forms a neutral solid that remains insoluble in alkali. On treatment with nitrous acid, it gives a yellow oily product without brisk evolution of nitrogen gas.
The unknown is most reasonably:

17. A (13.95 mathrm{g}) sample of aniline is treated with (12.42 mathrm{g}) of a sodium nitrite sample that is (80.0%) pure. Hydrochloric acid is in excess. Only (90.0%) of the limiting reagent undergoes diazotisation, and (85.0%) of the benzenediazonium chloride formed remains available in the cold reaction solution after handling losses. Calculate the mass equivalent of usable diazonium salt in solution and the mass of chemically unreacted aniline. Use (M(mathrm{aniline})=93.0 mathrm{g,mol^{-1}}), (M(mathrm{NaNO_2})=69.0 mathrm{g,mol^{-1}}), and (M(mathrm{C_6H_5N_2Cl})=140.5 mathrm{g,mol^{-1}}).

18. A coupling mixture contains (0.120 mathrm{mol}) of an arenediazonium salt and (0.100 mathrm{mol}) of phenol. Under buffered alkaline conditions, (90.0%) of the phenolic component is present as phenoxide at equilibrium. Because phenol and phenoxide rapidly interconvert, (80.0%) of the total phenolic component undergoes coupling, and the azo product is isolated in (75.0%) yield. If (M(mathrm{azo product})=198 mathrm{g,mol^{-1}}), calculate the isolated product mass and the amount of chemically unreacted diazonium salt.

19. Assertion: Sulphanilic acid is commonly represented as a zwitterion in the solid state.
Reason: A proton is transferred from the strongly acidic sulphonic acid group to the basic amino group, giving and groups.

20. Three compounds are listed below.
Compound P:
Compound Q:
Compound R:
The pair in which the nitrogen lone pair can interact directly with the benzene -system is:

21. A neutral amine is converted into its protonated ammonium ion. Its immediate nucleophilicity at nitrogen decreases mainly because:

22. A sample of -bromobutane is converted into pentan-1-amine through the nitrile route. If the overall yield is , what mass of pentan-1-amine is obtained? Use its molar mass as .

23. Use the following passage.
A student protects aniline by acetylation and then brominates the protected compound. Analysis shows a major product P and a smaller amount of product Q. Both products contain one bromine atom. Hydrolysis of P gives -bromoaniline.
Which conclusion is most consistent with the experiment?

24. The approximate hybridisation of nitrogen in an ordinary neutral amine is ______.

25. Examine the geometry assignments below.

The valid row is:

26. An unknown amine forms no sulphonamide with Hinsberg reagent, remains unreacted in excess alkali, and dissolves when dilute acid is added. The amine is:

27. The table lists standard nitrous-acid products.

The valid rows are:

28. When equal amounts of aniline and ethylamine are separately treated with a limited amount of the same strong acid, ethylamine is protonated more extensively because:

29. A graph plots boiling point on the vertical axis and carbon-atom count on the horizontal axis for a homologous series of straight-chain primary amines. The most reasonable overall shape is:

30. When trimethylamine forms a bond with a methyl group to produce , the nitrogen centre changes from:

31. An aqueous extract contains of ethylammonium chloride and of excess hydrochloric acid. It is treated with of sodium hydroxide. Given and , the final is approximately:

32. An unknown amine gives a positive carbylamine test. In a separate experiment, it reacts with benzenesulphonyl chloride, and the product dissolves in excess alkali but precipitates after acidification. Which conclusion is justified?

33. Assertion: Direct ammonolysis and Gabriel synthesis preserve the carbon count of a suitable alkyl halide, whereas the nitrile route increases it by one.
Reason: Cyanide introduces a carbon atom, while ammonia and phthalimide introduce nitrogen without contributing carbon to the final alkyl chain.

34. A graph plots moles of benzonitrile formed against moles of added to of benzenediazonium chloride. The reaction is quantitative. The graph shows:

35. The IUPAC name of is:

36. A student attempts to prepare pure -bromoaniline by adding a controlled small amount of bromine water directly to aniline. Why is this approach unreliable?

37. Use the following passage.
A primary aliphatic amine is diazotised in aqueous acid. The diazonium intermediate loses nitrogen rapidly. In a simple substrate, water capture gives the corresponding alcohol. In a more highly substituted or unsymmetrical substrate, the carbon intermediate may rearrange or follow competing pathways.
Which conclusion is most appropriate?

38. Assertion: One universal aqueous order such as secondary primary tertiary cannot safely be applied to every alkylamine set.
Reason: Changing the alkyl group changes both electron donation and solvation or steric effects.

39. Four sealed flasks P, Q, R, and S contain equal amounts of methylamine, ethylamine, propan--amine, and butan--amine, respectively. Each amine is treated quantitatively with excess nitrous acid under identical conditions. The resulting nitrogen volumes are described by:

40. A mixture contains methylamine, dimethylamine, and trimethylamine. Complete neutralisation shows that the mixture contains of total amines. The carbylamine test produces of isocyanide, while complete Hinsberg reaction consumes of benzenesulphonyl chloride. Using molar masses , , and , respectively, the amounts of the three amines and the total mixture mass are:

41. Two curves show the moles of bromine incorporated per mole of aromatic substrate under different conditions. Curve P rapidly approaches , while curve Q approaches . Which assignment is most appropriate?

42. A graph plots the fraction of a tertiary amine present in the aqueous phase against decreasing during extraction with hydrochloric acid. Which trend is most reasonable?

43. A solution is prepared by diluting of methylammonium chloride to . Given and , the approximate of the diluted solution is:

44. Consider the following statements about amine nomenclature.
Statement I: An -locant shows that a substituent is attached directly to nitrogen.
Statement II: A numerical carbon locant identifies a position on the selected parent chain.
Statement III: Two identical substituents on nitrogen may be written using -notation.
Select the applicable combination.

45. After an amine has been transferred into an aqueous layer as , treatment with excess sodium hydroxide followed by extraction with an organic solvent will mainly:

46. Complete conversion of of an unknown monofunctional amine gives its hydrochloride. The isolated hydrochloride weighs , and the isolation yield is . Assuming one mole of amine binds one mole of hydrochloric acid, the amine is:

47. -Bromopropane is converted into butanenitrile, which is hydrolysed to butanoic acid. The acid is converted into butanamide, and the amide undergoes Hoffmann degradation. The final product and its carbon count are:

48. An organic layer initially contains of aniline. It is extracted with enough hydrochloric acid to protonate only of aniline. The aqueous extract is then treated with of sodium hydroxide. If of the liberated aniline is finally isolated, which record is correct? Use .

49. Bond angles around nitrogen in an ordinary amine are generally slightly smaller than the ideal tetrahedral angle because:

50. The preferred conditions for preparing a primary alkylamine by ammonolysis of a haloalkane are: