Amines Mock Test – Class 12 Chemistry

1. Complete conversion of a methylamine–propan--amine mixture gives the corresponding -acetyl derivatives. The total product mass is . Each mole of amine gains during acetylation. Using amine molar masses and , respectively, the amounts of methylamine and propan--amine are:

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

3. The IUPAC name of is:

4. A bulky tertiary amine is found to be a stronger base in the gas phase than a less substituted amine, but a weaker base in water. Which explanation best reconciles the observations?

5. Catalytic hydrogenation of nitrobenzene to aniline may be carried out using:

6. Assertion: The gas-phase basicity order of methylamines should not be used automatically as their aqueous basicity order.
Reason: In water, solvation and steric accessibility of the conjugate acids compete with the electron-releasing effect of alkyl groups.

7. Three isomeric amines P, Q, and R have the formula . P has two bonds, Q has one bond, and R has none. Their most likely decreasing boiling-point order is:

8. 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 .

9. Stronger hydration of an ammonium ion can increase the aqueous basicity of its parent amine because hydration:

10. Using hydrochloric acid, a sample of an unknown weak monobasic amine is titrated. Equivalence occurs after of acid is added. At half-equivalence, the measured is at . The initial amine concentration and its are:

11. Which reagent sequence converts nitrobenzene into phenol?

12. A saturated acyclic monoamine has hydrogen atoms in one molecule. The number of carbon atoms present is:

13. Assertion: Nitrogen gas is evolved during Sandmeyer chlorination of benzenediazonium chloride.
Reason: The diazonium group leaves as stable molecular nitrogen while chlorine replaces it on the aromatic ring.

14. An organic solution contains a neutral amine mixed with a neutral hydrocarbon. Shaking the solution with dilute hydrochloric acid transfers the amine mainly into the aqueous layer because:

15. An organic mixture of mass contains aniline and a neutral compound. The aniline is completely extracted as its hydrochloride, regenerated with base, and isolated. The recovered aniline has a mass of , corresponding to an overall recovery. The original mass percentage of aniline and the minimum volume of hydrochloric acid required for extraction are:

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

17. Four operations are described below.
P: Prepare a substituted aromatic amine with the required ring-substitution pattern.
Q: Diazotise the amino group under cold acidic conditions.
R: Treat the diazonium species with nitrite under suitable copper-assisted conditions.
S: Obtain the corresponding nitroarene.
Which sequence is correct?

18. Which decreasing basicity order is most reasonable?

19. Assertion: Trimethylamine does not produce brisk nitrogen evolution when treated with cold nitrous acid.
Reason: Trimethylamine forms trimethylammonium nitrite mainly through an acid–base reaction.

20. Match each structure in Column I with its common name in Column II.

21. 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:

22. Which decreasing basicity order is most reasonable?

23. Under controlled bromination conditions, acetanilide gives a higher proportion of para monobromination than unprotected aniline because:

24. 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:

25. Assertion: Direct nitration of aniline does not give only ortho- and para-nitroaniline.
Reason: The strongly acidic nitrating medium converts a significant fraction of aniline into anilinium ion, which is meta directing.

26. To prepare propan-1-amine, the appropriate starting amides for reduction and Hoffmann degradation, respectively, are:

27. Two compounds have the same molecular formula . Compound P contains an group, while compound Q has no nitrogen-bonded hydrogen. The most suitable conclusion is:

28. A sample of acetanilide is nitrated. The chemical conversion to mononitroacetanilide is , and of the converted material forms the para isomer. The para product is isolated in yield. Using and , the isolated mass is:

29. When a haloalkane is present in large excess relative to ammonia, the product distribution is pushed most strongly toward:

30. Ordinary Friedel–Crafts alkylation or acylation of aniline generally fails under standard -catalysed conditions because:

31. 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 .

32. Consider the following statements about diazonium-salt stability.
Statement I: Arenediazonium salts are relatively stable in cold aqueous solution.
Statement II: Aliphatic diazonium ions are generally less stable than aromatic diazonium ions.
Statement III: Dry diazonium salts should be handled cautiously because some may decompose explosively.
Statement IV: Heating always increases the storage stability of diazonium salts.
Select the applicable combination.

33. 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:

34. Four bases have the following values at the same temperature. Which is the strongest base?

35. A graph plots moles of benzenediazonium chloride formed against moles of sodium nitrite added to of aniline in excess hydrochloric acid at . Diazotisation is quantitative. The graph follows:

36. Tertiary aromatic and tertiary aliphatic amines show different behaviour with nitrous acid mainly because:

37. 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?

38. Evaluate the three statements below.
Statement I: Ammonia is not classified as a primary amine because no carbon group is bonded to nitrogen.
Statement II: A species of the form is a quaternary ammonium ion.
Statement III: Every tertiary amine must contain three bonds.
Select the applicable combination.

39. Assertion: Acylation of aniline decreases its basicity.
Reason: The nitrogen lone pair of the resulting anilide becomes delocalised into the carbonyl group.

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

41. A mixture contains ethylamine and triethylamine. Treatment with excess benzoyl chloride under alkaline conditions gives of -ethylbenzamide, molar mass . After removal of the amide, the remaining base requires of hydrochloric acid. The original masses of ethylamine and triethylamine are:

42. A freshly prepared cold aqueous preparation contains (25.0 mathrm{g}) of dissolved solids consisting of benzenediazonium chloride and inert impurities. Complete Sandmeyer bromination produces (2.24 mathrm{L}) of nitrogen at STP, and bromobenzene is isolated in (80.0%) yield. Using (22.4 mathrm{L,mol^{-1}}) at STP, (M(mathrm{C_6H_5N_2Cl})=140.5 mathrm{g,mol^{-1}}), and (M(mathrm{bromobenzene})=157 mathrm{g,mol^{-1}}), the mass percentage of benzenediazonium chloride in the dissolved solids and the isolated bromobenzene mass are:

43. When -dimethylaniline is treated with nitrous acid under suitable conditions, the principal organic product is:

44. A mixture of of triethylamine and of bromoethane is heated to form tetraethylammonium bromide. The limiting reagent reacts completely, but only of the salt formed is isolated. Using molar masses , , and , respectively, the isolated salt mass and the mass of unreacted triethylamine are:

45. Replacement of the diazonium group by a nitro group can be achieved at recognition level by treating a suitable arenediazonium species with:

46. 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 .

47. Assertion: A tertiary amine can be separated from a secondary-amine Hinsberg product by treatment with dilute hydrochloric acid.
Reason: The tertiary amine forms a soluble ammonium salt, whereas the neutral secondary sulphonamide does not undergo the same protonation-solubility change.

48. The structure represents:

49. Aniline, , is diazotised with conversion. Sandmeyer cyanation converts of the diazonium salt formed into benzonitrile. Hydrolysis converts of that benzonitrile into benzoic acid. Calculate the benzoic acid mass and the volume of nitrogen evolved during the cyanation step at STP. Use , , and at STP.

50. Which reagent sequence most suitably converts aniline into mainly -nitroaniline?