Amines Mock Test – Class 12 Chemistry

1. Equal initial amounts of benzenediazonium ion and an aliphatic diazonium ion are maintained at the same low temperature. A graph plots the fraction of each ion remaining against time. Which description is most reasonable?

2. Aniline, , is acetylated quantitatively. The resulting acetanilide is nitrated using of nitric acid, of which only reacts. Assume one mole of nitric acid produces one mole of mononitroacetanilide, of the nitrated material is the para isomer, and hydrolysis of that isomer gives -nitroaniline in yield. Using and , the final product mass is:

3. An unknown compound has molecular formula . It gives a positive carbylamine test and can be prepared by reduction of a nitrile obtained from -bromopropane and alcoholic . The unknown is:

4. The mixture contains methylamine and dimethylamine. Complete neutralisation requires of hydrochloric acid. When a separate identical mixture is treated with excess nitrous acid, of nitrogen is obtained at STP. Assuming at STP, the amounts of methylamine and dimethylamine and the mass percentage of methylamine are:

5. The appropriate sequence for obtaining free aniline from nitrobenzene using an acidic metal reduction is:

6. The structure is named:

7. Assertion: -Methylaniline and -methylaniline require different locant styles.
Reason: The methyl group is attached to nitrogen in the first compound and to a numbered ring carbon in the second.

8. 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:

9. Compare the diazonium conversions below.

The valid rows are:

10. 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:

11. Assertion: -Methylaniline can be less basic than -methylaniline even though the methyl group is electron releasing in both compounds.
Reason: The ortho methyl group can hinder proton approach and hydration of the protonated amine.

12. Examine the constant pairs below.

The internally consistent row is:

13. Assertion: In , the amino group is named using the prefix “amino.”
Reason: The carboxylic acid group has higher nomenclature priority than the amino group.

14. Assertion: The carbon atom of the nitrile group in benzonitrile obtained by Sandmeyer cyanation does not come from aniline.
Reason: The nitrile carbon is introduced by the cyanide supplied through .

15. 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.

16. In an important resonance contributor of aniline formed by donation of the nitrogen lone pair into the benzene ring:

17. A graph plots moles of trimethylammonium nitrite and moles of nitrogen gas against moles of nitrous acid added to of trimethylamine. Under ordinary cold conditions, the graph shows:

18. Benzenediazonium chloride is normally kept in cold aqueous solution because:

19. Benzamide is converted into aniline by Hoffmann degradation. The aniline is diazotised, treated with , and the nitrile is hydrolysed to benzoic acid. The carbon bookkeeping is:

20. An unknown aromatic nitrogen compound gives a positive carbylamine test, forms a white precipitate with bromine water without a Lewis acid catalyst, and produces a cold diazonium salt that gives phenol on warming. The matching set is:

21. An unreacted tertiary amine from a Hinsberg test dissolves when dilute hydrochloric acid is added because:

22. Benzoylation of a impure aniline sample uses excess benzoyl chloride and sodium hydroxide. The isolated benzanilide mass is , corresponding to an yield. Using molar masses for aniline and for benzanilide, the percentage purity of aniline and the minimum volume of sodium hydroxide theoretically required are:

23. Iron is often preferred over tin for large-scale acidic reduction of nitrobenzene mainly because iron:

24. In the Brønsted–Lowry description, an amine behaves as a base when it:

25. Assertion: Potassium iodide converts benzenediazonium chloride into iodobenzene with evolution of nitrogen gas.
Reason: The diazonium group is replaced by iodide ion, while its two nitrogen atoms leave as stable .

26. A fixed amount of of a primary amine is heated with increasing amounts of chloroform while alcoholic potassium hydroxide remains in excess. A graph plots moles of isocyanide formed on the vertical axis against moles of chloroform added on the horizontal axis. Which description is correct?

27. Match each stage in Column I with its corresponding role or product in Column II.

28. Benzamide is subjected separately to reduction and Hoffmann degradation. The respective products are:

29. Benzenediazonium chloride is prepared from aniline by treating it with:

30. Assertion: Aniline reacts rapidly with bromine water without addition of .
Reason: The amino group strongly activates the ring through resonance donation and stabilises the substitution intermediate.

31. A mixture contains methylamine and dimethylamine. On complete carbylamine reaction, of isocyanide is formed. What is the mass percentage of methylamine in the mixture, and what mass of potassium hydroxide is theoretically consumed? Use and .

32. Examine the predicted carbylamine-test results below.

The valid rows are:

33. Assertion: Hoffmann bromamide degradation of benzamide gives aniline.
Reason: The phenyl group migrates from the carbonyl carbon to nitrogen, while the carbonyl carbon is removed.

34. A sample of ethylamine is treated with nitrous acid. Only of the amine reacts, and of the nitrogen formed is collected over water at . The total pressure is , and the vapour pressure of water is . Calculate the collected wet-gas volume. Use and .

35. The aqueous basicity order of ethyl-substituted amines is commonly represented as:

36. Which decreasing basicity order is most reasonable?

37. A mixture contains a primary, a secondary, and a tertiary amine. A suitable Hinsberg separation sequence is:

38. A sample of aniline is converted into sulphanilic acid. The chemical conversion is , and the product is isolated in yield. Calculate the isolated product mass and the mass of concentrated sulphuric acid theoretically consumed the converted material. Use , , and .

39. Three reaction vessels are arranged as follows.
Vessel P contains -dimethylaniline with its para position free.
Vessel Q contains -methyl--dimethylaniline.
Vessel R contains trimethylamine.
All three are treated separately with cold nitrous acid under conditions suitable for their standard reactions. The principal outcomes for P, Q, and R, respectively, are:

40. 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?

41. Interchanging the two ethyl groups in diethylamine does not produce a new constitutional isomer because:

42. A reaction mixture contains of aniline, of ethanoyl chloride, and of sodium hydroxide. Only of the ethanoyl chloride reacts, all the acetanilide formed is isolated, and hydrolysis of unreacted ethanoyl chloride is neglected. Using molar masses , , , and , respectively, the mass of acetanilide formed and the mass of sodium hydroxide remaining are:

43. Benzylamine and aniline are treated separately with cold nitrous acid. Their contrasting outcomes are:

44. Match each factor in Column I with its principal effect in Column II.

45. The structure corresponding to -methylbutan-2-amine is:

46. A structure has the formula . Its proper IUPAC name is:

47. Why should odour alone not be used to identify an unknown amine?

48. Relative electrophilic-substitution rate is plotted against the fraction of aniline present as anilinium ion. Which overall trend is most reasonable?

49. Which statement most accurately distinguishes basicity from nucleophilicity?

50. Examine the reaction records below.

The valid row is: