Organic Compounds Containing Nitrogen Mock Test – NEET Chemistry

1. A compound contains a free primary aromatic amino group and a tertiary aliphatic amino group:

It is subjected to the following sequence:
(i) Diazotisation at the aromatic primary amino site under suitably cold acidic conditions.
(ii) Replacement of the diazonium group with fluorine using the tetrafluoroborate method.
(iii) Treatment of the resulting compound with excess hydrochloric acid, followed by sufficient aqueous sodium hydroxide.
Assume no substitution at the benzylic tertiary amino group and no cleavage of its N–C bonds.
Which statement correctly describes the final neutral organic product?

2. Benzenediazonium chloride is reacted with N,N-dimethylaniline under suitable azo-coupling conditions.
The para position of the N,N-dimethylamino-substituted ring is initially unoccupied.
A student predicts that no azo compound can form because N,N-dimethylaniline has no N–H bond.
Which statement correctly evaluates this prediction?

3. A proposed industrial synthesis uses an aromatic primary amine as a starting intermediate to prepare an azo-coloured compound.
The chemist considers two alternatives.
Route P: Convert the aromatic primary amine into its diazonium salt and carry out a suitable coupling reaction.
Route Q: Convert the aromatic primary amine into its diazonium salt and replace the diazonium group by hydrogen.
Which inference best explains why P is appropriate for the stated objective?

4. Three amines are represented by the following structures:
P:
Q:
R:
A simple amine contains identical organic groups attached to nitrogen, whereas a mixed amine contains different organic groups.
Which statement is correct?

5. Three neutral nitrogen-containing compounds are represented by:
P:
Q:
R:
A chemist wishes to distinguish the consequences of three different interactions involving the nitrogen lone pair:
(i) direct nitrogen-to-ring conjugation;
(ii) competing nitrogen-to-carbonyl conjugation;
(iii) protonation of an N–H-free aromatic tertiary amine.
Which matching is correct?

6. A chemist wishes to prepare 4-fluorobenzaldehyde from 4-aminobenzaldehyde.
The following route is proposed:
(i) Convert the primary aromatic amino group into its corresponding diazonium tetrafluoroborate under appropriate cold conditions.
(ii) Heat the isolated diazonium tetrafluoroborate under conditions producing the aryl fluoride.
Assume the aldehyde group is preserved during the stipulated transformations.
A student proposes replacing step (i) with direct treatment of the amino compound with hydrogen fluoride, arguing that fluoride should simply displace the amino group.
Which statement correctly evaluates the proposal?

7. Sulphanilic acid is 4-aminobenzenesulfonic acid, containing an aromatic amino group and a sulfonic acid group at para positions.
It is diazotised under appropriate cold conditions, and the resulting aromatic diazonium species is coupled with N,N-dimethylaniline at the para position of its N,N-dimethylamino-substituted ring.
Which statement correctly describes the principal azo product?

8. Diphenylamine, , and N-methylaniline, , are compared.
Consider the following statements.
Statement I: Both compounds are secondary aromatic amines.
Statement II: Both possess an N–H bond and can undergo ordinary N-acylation with a suitable acyl chloride.
Statement III: Diphenylamine has two aromatic groups directly bonded to nitrogen, allowing its lone pair to interact with two aromatic systems.
Statement IV: Both compounds must give a positive carbylamine test because each contains a nitrogen-bound hydrogen.
Which combination is correct?

9. Four substances are examined at 273–278 K.

Which statement correctly identifies the significance of the initial nitrogen substitution and protonation states?

10. A chemist wishes to prepare 4-aminobenzaldehyde from aniline while ensuring that the final aromatic amino nitrogen originates from an initially introduced nitro group rather than from the amino group of the starting aniline.
The following transformations are available:
P: Convert aniline into benzenediazonium chloride, then perform Sandmeyer cyanation.
Q: Convert the resulting aromatic nitrile into the corresponding aldehyde through controlled DIBAL-H reduction and hydrolytic work-up.
R: Introduce a nitro group para to the original amino group before removing that amino group.
S: Selectively reduce the introduced nitro group to an amino group while preserving the aldehyde.
A student proposes using R → P → Q → S, with the original amino group retained until it has been diazotised and replaced by cyanide.
Assume the specified positional nitration and chemoselective reductions are successful.
Which statement correctly assesses the carbon and nitrogen origins in the final product?

11. A primary amide X undergoes Hofmann bromamide degradation to give butan-2-amine. When another sample of X is treated with in dry ether, followed by hydrolytic work-up, a different primary amine Y is obtained.
Which pair correctly identifies X and Y?

12. An equimolar mixture of 4-aminophenol and aniline is completely diazotised at 273–278 K.
Under the stipulated conditions, the resulting diazonium groups are stable in the cold solution.
The two diazonium salts are then separated without decomposition.
Each salt is independently coupled quantitatively with one mole equivalent of phenol under conditions favouring para coupling on the added phenol ring.
The resulting neutral azo products are examined for their numbers of phenolic hydroxyl groups.
Which statement correctly compares the products?

13. Two haloarenes are treated separately with ammonia under suitably vigorous nucleophilic aromatic substitution conditions.
P: 1-Chloro-4-nitrobenzene.
Q: 1-Chloro-3-nitrobenzene.
Assume that the conditions permit appreciable chlorine replacement in P, while Q reacts much less readily through the corresponding ordinary nucleophilic aromatic substitution pathway.
The principal substitution product from P is subsequently subjected to complete selective nitro-group reduction.
Which statement correctly identifies the final product from P and explains the different reactivities of P and Q?

14. Two aromatic compounds are compared:
P: 2-Methylbenzenamine.
Q: N-Methylbenzenamine.
Each is separately treated with ethanoyl chloride and pyridine under conditions allowing complete ordinary N-acetylation.
The acetylated products are then subjected to controlled aromatic bromination.
Which statement correctly describes the different locations of their original methyl groups and the nitrogen functionalities after acetylation?

15. A molecule contains two nitrogen atoms in the following groups:
P: , attached directly to an aromatic carbon.
Q: , attached to the same aromatic ring through the methylene carbon.
A student proposes that treatment with dilute hydrochloric acid must protonate P preferentially because P contains an N–H bond while Q does not.
Which statement correctly evaluates the proposal?

16. A chemist is given four candidate compounds having the molecular formula :
P: Benzylamine
Q: 2-Methylaniline
R: 3-Methylaniline
S: 4-Methylaniline
An unknown X gives a positive carbylamine test and forms a diazonium salt in cold acidic nitrite solution at 273–278 K. On controlled bromination, its aromatic substitution pattern shows two positions related by symmetry that are ortho to the amino group, while the para position is occupied by a methyl group.
Which compound is X?

17. A chemist has isolated a compound with two benzene rings connected by an linkage.
One ring bears a hydroxyl group para to the azo linkage, while the other ring bears a nitro group meta to that linkage.
The compound was prepared by coupling an arenediazonium salt with phenol under suitable alkaline conditions.
Which primary aromatic amine is the appropriate precursor for the diazonium component?

18. Benzene is converted into 1,3-dinitrobenzene by successive nitration under suitable conditions. The objective is to prepare 3-fluoroaniline without changing the relative positions of the two original nitro substituents.
The following operations are available:
P: Selective reduction of exactly one nitro group to a primary aromatic amino group.
Q: Diazotisation of the free amino group at 273–278 K, followed by treatment with tetrafluoroboric acid and controlled thermal decomposition of the diazonium tetrafluoroborate.
R: Complete reduction of the remaining nitro group to an amino group.
Assume that each transformation is chemoselective and preserves the other substituent.
Which statement correctly identifies the required sequence and the origin of the final amino nitrogen?

19. A chemist wishes to prepare 4-bromoaniline as the major product starting from aniline while avoiding extensive bromination.
Which sequence is the most suitable?

20. Four independent preparations of nitrogen-containing organic compounds are proposed in the following table. All work-ups necessary to obtain the stated free amines are assumed to be performed.

Which combination contains all the correctly predicted products?

21. Two primary aromatic amines are compared:
P: 4-Nitroaniline.
Q: 4-Methoxyaniline.
Each is treated separately with a sufficient strong mineral acid to form its conjugate acid.
A student predicts that the aromatic ring bearing the stronger basic amino group must also be the less electron-rich ring under all conditions.
Which statement correctly distinguishes amino-group basicity from aromatic ring activation?

22. Consider the following assertion and reason.
Assertion (A): A positive carbylamine reaction with chloroform and ethanolic potassium hydroxide establishes that an unknown amine is primary, but does not by itself establish whether it is an aliphatic or aromatic primary amine.
Reason (R): Both primary aliphatic and primary aromatic amines contain the N–H functionality required for the reaction and can form the corresponding isocyanides.
Choose the correct option.

23. Two weak aromatic bases P and Q are dissolved in separate solutions that are subsequently adjusted to the same pH.
Their analytical concentrations and conjugate-acid pKa values are:

For each base, the equilibrium concentration of the neutral form is given by:

Assume ideal acid–base equilibria and negligible interactions between different solutes.
At what common pH will the concentrations of neutral P and neutral Q be equal?

24. A mixture contains of propan-1-amine, of N-methylpropan-1-amine and of aniline.
The mixture is treated with sufficient nitrous acid, generated in situ from sodium nitrite and hydrochloric acid, at .
Assume complete, selective reactions under conditions where the primary aliphatic amine liberates nitrogen gas, the secondary amine forms its N-nitroso derivative, and the primary aromatic amine forms an arenediazonium salt that is used before decomposition.
What are the amounts of nitrogen gas evolved and arenediazonium salt formed, respectively?

25. A mixture contains only ethanamine (P), diethylamine (Q) and triethylamine (R).
Its total amount is .
The mixture is treated with excess benzenesulphonyl chloride under conditions giving complete ordinary sulphonamide formation from primary and secondary amines.
The following observations are made:
(i) The total amount of N-sulphonyl products formed is .
(ii) Exactly of these products dissolve in aqueous sodium hydroxide because they possess an acidic sulphonamide N–H bond.
(iii) No other acidic functional groups affect the solubility results.
Which option gives the original amounts of P, Q and R, respectively?

26. The following boiling-point data are supplied from the NCERT discussion of amines:

All four compounds have the same molecular formula except that S contains oxygen in place of nitrogen and has the corresponding different hydrogen count.
A student argues that R cannot accept hydrogen bonds from water because it has the lowest boiling point among the three amines.
Which statement correctly interprets the data and evaluates this argument?

27. The pKb values of three amines in water at 298 K are supplied:

A student claims that the aqueous basicity order should be R Q P because increasing alkyl substitution always increases the positive inductive effect.
Which statement correctly identifies the strongest aqueous base and the conceptual defect in the student's reasoning?

28. A dilute aqueous solution of a primary aliphatic amine B is prepared at 298 K.
Its experimentally measured base dissociation constant is:

The analytical amine concentration is:

For the equilibrium:

assume that water autoionisation is negligible, activities can be replaced by concentrations, and no other equilibria are significant.
Which option gives the approximate percentage of amine protonated and the solution pH, respectively?

29. An arenediazonium salt is subjected to two different reactions.
Reaction P: Treatment with warm water.
Reaction Q: Coupling with phenol in an appropriate alkaline medium, with the para position relative to hydroxyl initially unoccupied.
Which statement correctly distinguishes the fate of the diazonium nitrogen atoms?

30. A student claims that a tertiary amine must have an approximately tetrahedral molecular shape around nitrogen because the nitrogen atom is ordinarily described as hybridised.
Consider the following statements.
Statement I: In a neutral tertiary aliphatic amine, nitrogen has three sigma bonds and one lone pair.
Statement II: The arrangement of electron-pair regions around nitrogen is approximately tetrahedral, but the arrangement of the three bonded atoms is pyramidal.
Statement III: Protonation can replace the lone-pair region with an additional N–H bonding region.
Statement IV: The presence of four electron-pair regions requires four atoms to be bonded directly to nitrogen in every neutral amine.
Which combination is correct?

31. Glycine, , is treated with sufficient nitrous acid under conditions that quantitatively convert its primary aliphatic amino group into a hydroxyl group without altering the carboxyl group.
Which statement correctly identifies the principal organic product and the number of moles of nitrogen evolved per mole of glycine?

32. A student wishes to prepare 3-bromoaniline as the principal product starting from benzene. Which sequence of reactions provides the most appropriate route?

33. Consider the following sequence beginning with methanamine:

The product Q is then treated with nitrous acid under suitable conditions for its amine class.
Which statement correctly describes the transformation and the characteristic nitrous-acid product?

34. A chemist prepares benzenediazonium chloride from aniline at 273–278 K.
The cold solution is divided into three equal portions and subjected to the following operations:
P: Treatment with aqueous potassium iodide.
Q: Treatment with aqueous copper(I) cyanide.
R: Treatment with aqueous sodium nitrite in the presence of copper after conversion to the corresponding diazonium tetrafluoroborate.
Assume complete replacement of the diazonium group and no competing transformations.
Which statement correctly compares the origins of the atoms introduced at the former amino-bearing aromatic carbon?

35. Aniline is to be converted into 2,4,6-tribromobenzonitrile without changing the positions of the three bromine substituents once introduced.
The following operations are available:
P: Treatment with excess bromine water.
Q: Diazotisation using at 273–278 K.
R: Sandmeyer cyanation using under suitable conditions.
S: Replacement of an aromatic diazonium group by hydrogen using .
Assume that the specified substitutions proceed quantitatively and that existing aromatic carbon–bromine bonds are preserved.
Which sequence gives the desired product, and what is the origin of its nitrile carbon?

36. Direct nitration of aniline using a concentrated nitric acid–sulfuric acid mixture may produce significant quantities of the meta-nitro derivative, even though the free amino group is ortho/para directing.
Which explanation correctly accounts for this observation?

37. Consider the following reaction schemes involving aniline.
Scheme I:

Scheme II:

Scheme III:

Which statement is correct?

38. An organic compound has the structure .
Which option correctly gives its IUPAC name and classification?

39. A student compares two proposed coupling experiments using freshly prepared benzenediazonium chloride.
Experiment P uses phenol in an appropriately alkaline medium.
Experiment Q uses benzene in the same medium, without any additional activating substituent or special coupling conditions.
Which statement provides the best chemical assessment?

40. At , the aqueous pKb values of aniline and benzylamine are 9.38 and 4.70, respectively.
For each amine B, define:

Both compounds are present in the same buffered aqueous solution at a fixed pH.
Given , determine:

41. A chemist starts with benzene-1,4-diamine and selectively converts exactly one of its amino groups into an acetamido group.
The remaining amino group is diazotised and coupled with phenol under conditions giving complete monoazo coupling.
After isolation of the azo product, the N-acetyl group is completely hydrolysed without affecting the azo linkage.
The product is then subjected to an ordinary carbylamine test.
Which statement correctly predicts the result and explains the role of the protecting group?

42. A chemist wishes to prepare benzene-1,3-diamine from benzene.
Three operations are available:
P: Nitration with concentrated under suitable conditions.
Q: Further nitration under conditions sufficiently vigorous to nitrate nitrobenzene.
R: Complete reduction of all nitro groups using a suitable reducing system, followed by liberation of the free amino groups.
Two strategies are proposed:
Strategy I: P → Q → R.
Strategy II: P → R, followed by ordinary nitration of the resulting amine under strongly acidic conditions and reduction of the newly introduced nitro group.
Which statement correctly assesses the strategies?

43. A weak base B has at 298 K.
A solution of B is prepared.
Assume that B accepts one proton, that water autoionisation is negligible and that the equilibrium is:

A student uses the approximation to calculate the hydroxide concentration, but the experimental conditions require checking whether the approximation is justified.
Given and , which option gives the closest equilibrium hydroxide concentration and correct assessment?

44. A neutral organic compound contains a primary aromatic amino group and a carboxylic acid group attached to the same benzene ring.
It is subjected separately to the following treatments:
P: Dilute aqueous hydrochloric acid.
Q: Aqueous sodium hydroxide.
R: Ethanoyl chloride in the presence of pyridine under conditions favouring N-acylation.
Which statement correctly identifies the functional-group changes?

45. A molecule contains two differently substituted amino groups:

One amino nitrogen belongs to a benzylic primary amino group.
The other belongs to a secondary aromatic amino group.
The molecule is subjected to sufficient nitrous acid under conditions that:
(i) Quantitatively convert the benzylic primary amino group into a hydroxymethyl group with nitrogen evolution.
(ii) Quantitatively convert the secondary aromatic amino group into its N-nitroso derivative without nitrogen-gas evolution from that site.
(iii) Preserve the aromatic carbon skeleton and prevent other nitrosation reactions.
Which statement correctly identifies the principal organic product and the source of the evolved nitrogen gas?

46. The compound 4-(aminomethyl)aniline has the structure:

It contains two primary amino groups. In a sufficiently dilute aqueous solution, a limited amount of hydrochloric acid is added so that formation of the monoprotonated species is favoured.
Ignoring interactions between the two sites other than their ordinary electronic effects, which nitrogen is expected to be protonated preferentially?

47. Consider the following sequence beginning with 1-bromo-2-methylpropane:

A second sample of the same alkyl bromide undergoes Gabriel phthalimide synthesis under suitable conditions to give R.
Assume complete substitution through the carbon end of cyanide in the first pathway and no rearrangement in either pathway.
Which statement correctly identifies Q and R and compares their parent carbon skeletons?

48. A solution contains an unknown primary amine X and an unknown secondary amine Y.
Both are saturated, acyclic monoamines with the same molecular formula .
The following experiment is performed:
(i) A sample of the mixture is treated with excess benzoyl chloride under conditions giving one ordinary N-benzoylation per amine molecule.
(ii) The isolated N-benzoyl products are analysed for the presence of a remaining N–H bond.
(iii) The products containing an N–H bond constitute of the total benzoylated product molecules.
Which statement correctly describes the starting mixture?

49. 4-Nitroaniline is subjected to bromination using sufficient bromine under conditions that introduce bromine at both available positions ortho to its amino group. The isolated dibrominated compound is then treated with , followed by sufficient aqueous sodium hydroxide.
Assume the bromine substituents remain unchanged during reduction.
What is the final organic product?

50. Two independently protonatable amines P and Q are present in a strongly buffered aqueous solution at pH 7.00.
Their analytical concentrations and conjugate-acid pKa values are:

Assume ideal equilibria and that each amine accepts only one proton.
Use:

Which statement correctly compares the equilibrium concentrations of protonated P and protonated Q?