Q&A for Amines (JEE/NEET Focus)

 over 100 short question-and-answer pairs focusing on the properties, reactions, and concepts of Amines, relevant for Class 12 NCERT, JEE, and NEET preparation.

Part 1: Classification and Nomenclature

Q. No.	Question	Answer
1	Define an Amine.	Organic compounds derived from ammonia (NH3​) by replacing one or more H atoms with alkyl or aryl groups.
2	Classify CH3​NH2​ as 1∘,2∘, or 3∘ amine.	Primary (1∘) amine (one alkyl group attached to N).
3	Classify (CH3​)2​NH as 1∘,2∘, or 3∘ amine.	Secondary (2∘) amine (two alkyl groups attached to N).
4	Classify (CH3​)3​N as 1∘,2∘, or 3∘ amine.	Tertiary (3∘) amine (three alkyl groups attached to N).
5	What is the IUPAC name for C6​H5​NH2​?	Aniline (or Benzenamine).
6	What is the IUPAC name for CH3​NHCH2​CH3​?	N-Ethylethanamine.
7	What is the hybridization of the nitrogen atom in simple amines?	sp3 hybridization.
8	What is the geometry around the nitrogen atom in amines?	Pyramidal (due to the presence of a lone pair).
9	Why are amines considered basic?	Due to the presence of the unshared pair of electrons on the nitrogen atom (acts as a Lewis base).

Part 2: Preparation of Amines

Q. No.	Question	Answer
10	What is the starting material for Ammonolysis?	Alkyl Halides (R−X).
11	What is the major drawback of Ammonolysis?	It yields a mixture of 1∘,2∘,3∘ amines and quaternary ammonium salt.
12	What condition maximizes the yield of the 1∘ amine in Ammonolysis?	Using a large excess of NH3​.
13	Name the reaction used to prepare 1∘ amine by reducing an amide with LiAlH4​.	Amide Reduction.
14	What is the advantage of reducing nitriles (RCN) to primary amines (RCH2​NH2​)?	It results in an amine with one more carbon atom (Ascent of series).
15	Name the reaction that converts a primary amide to a primary amine with one less carbon atom.	Hofmann Bromamide Degradation (or reaction).
16	What are the key reagents in the Hofmann Bromamide Degradation?	Br2​ and aqueous or alcoholic NaOH (or KOH).
17	Name the reaction used to prepare primary amines by reduction of nitro compounds (RNO2​).	Reduction of Nitro compounds (using Fe/HCl or Sn/HCl).
18	What is the unique characteristic of the Gabriel Phthalimide Synthesis?	It yields only pure primary (1∘) amines.
19	Can Aniline (C6​H5​NH2​) be prepared by Gabriel Phthalimide Synthesis?	No, aryl halides do not undergo SN​2 reaction easily.
20	What is the product when an oxime (R2​C=NOH) is reduced?	Primary (1∘) amine.

Part 3: Physical Properties and Basicity

Q. No.	Question	Answer
21	Why do 1∘ and 2∘ amines have higher boiling points than non-polar compounds of similar mass?	Due to Intermolecular Hydrogen Bonding.
22	Which amine (1∘,2∘, or 3∘) has the strongest intermolecular H-bonding?	Primary (1∘) amine (has two H atoms on N).
23	Why do 3∘ amines have lower boiling points than 1∘ and 2∘ amines?	Lack of H atom on nitrogen prevents intermolecular H-bonding.
24	Are lower aliphatic amines soluble in water?	Yes, due to their ability to form hydrogen bonds with water molecules.
25	How does the solubility of amines change with increasing molar mass?	Decreases (due to increased non-polar hydrocarbon part).
26	What is the common smell of low molecular weight amines?	Fishy smell or ammonia-like.
27	What determines the basic strength of an amine?	The ease of donation of the lone pair of electrons on the nitrogen atom.
28	How does an Electron-Donating Group (EDG) affect the basicity of an amine?	Increases basicity (stabilizes the resulting ammonium ion).
29	How does an Electron-Withdrawing Group (EWG) affect the basicity of an amine?	Decreases basicity (destabilizes the resulting ammonium ion).
30	How is pKb​ related to basic strength?	Lower pKb​ means a stronger base.
31	What factor dominates the basicity order of amines in the gaseous phase?	Inductive effect (3∘>2∘>1∘>NH3​).
32	What factors affect the basicity order of amines in aqueous solution?	Inductive effect, Solvation effect, and Steric hindrance.
33	What is the basicity order of methylamines in aqueous solution?	2∘>1∘>3∘>NH3​ (Me2​NH>MeNH2​>Me3​N).
34	What is the basicity order of ethylamines in aqueous solution?	2∘>3∘>1∘>NH3​ (Et2​NH>Et3​N>EtNH2​).
35	Why is Aniline a much weaker base than aliphatic amines?	The lone pair on N is delocalized into the benzene ring by resonance, making it less available for protonation.
36	What is the effect of an EWG (like -NO2​) on the basicity of Aniline?	Decreases basicity strongly (especially at o/p positions).
37	What is the effect of an EDG (like -CH3​) on the basicity of Aniline?	Increases basicity slightly.

Part 4: Chemical Reactions

Q. No.	Question	Answer
38	What is the reaction of amines with acetyl chloride (CH3​COCl) called?	Acylation (Nucleophilic Substitution).
39	What is the product of the acylation of a 1∘ amine?	A Substituted Amide (RCONH-R).
40	Which amines (1∘,2∘, or 3∘) undergo acylation?	Primary (1∘) and Secondary (2∘) amines (must have an H on N).
41	Name the reaction of amines with Benzoyl Chloride (C6​H5​COCl) in aqueous NaOH.	Benzoylation (or Schotten-Baumann reaction).
42	What is the product when an amine reacts with carbon disulphide (CS2​)?	An Isothiocyanate (Hoffmann Carbylamine Test intermediate).
43	What is the Carbylamine Reaction (Isocyanide Test) used for?	To distinguish and confirm the presence of Primary (1∘) amines only.
44	What are the key reagents for the Carbylamine Reaction?	Chloroform (CHCl3​) and alcoholic KOH (heat).
45	What is the characteristic observation of the Carbylamine Reaction?	Production of a Foul-smelling Isocyanide (R−NC).
46	What is the product when Aniline is acetylated?	Acetanilide (C6​H5​NHCOCH3​).
47	Why is the Amino group protected by acetylation before nitration of Aniline?	To reduce its strong activating power and prevent oxidation.
48	What is the product when Aniline is subjected to bromination using Br2​ water?	2,4,6-Tribromoaniline (a white precipitate).
49	What is the characteristic reaction of Aniline with NaNO2​/HCl at 0−5∘C?	Diazotization (formation of Benzene Diazonium Chloride).
50	What is the product when a Primary Aliphatic Amine reacts with HNO2​?	Alcohol (R−OH) with evolution of N2​ gas (unstable diazonium salt).
51	What is the product when a Secondary Amine reacts with HNO2​?	N-Nitrosoamine (a yellow oily compound).
52	What is the final product when Aniline reacts with Fuming H2​SO4​?	Sulphanilic Acid (Sulphonation).
53	What is the term for the product Sulphanilic Acid where NH3+​ and SO3−​ charges are present?	Zwitter ion (Dipolar ion).

Part 5: Hinsberg's Test and Distinction

Q. No.	Question	Answer
54	What is Hinsberg's Reagent?	Benzene Sulphonyl Chloride (C6​H5​SO2​Cl).
55	What is the purpose of Hinsberg's Test?	To distinguish and separate 1∘,2∘, and 3∘ amines.
56	What is the reaction type when a 1∘ amine reacts with Hinsberg's reagent?	Sulphonation (followed by salt formation).
57	What is the key observation for a Primary Amine in Hinsberg's Test?	The product is soluble in KOH (due to the acidic H on N).
58	What is the key observation for a Secondary Amine in Hinsberg's Test?	The product is insoluble in KOH (lacks acidic H on N).
59	What is the key observation for a Tertiary Amine in Hinsberg's Test?	No reaction (remains insoluble in both KOH and water).
60	What is the final product of 1∘ amine reaction with Hinsberg's reagent followed by KOH?	A Sulphonamide salt (water soluble).
61	What is the final product of 2∘ amine reaction with Hinsberg's reagent?	An N,N-Dialkylsulphonamide (insoluble).
62	Why is the product of 1∘ amine and Hinsberg's reagent acidic?	Due to the presence of a highly polar N-H bond.
63	What is the solubility of 3∘ amine in Hinsberg's test?	The 3∘ amine itself may dissolve in HCl (but is separated easily).
64	Give one test to distinguish Ethylamine (1∘) from Diethylamine (2∘).	Carbylamine Test (Ethylamine gives foul smell, Diethylamine does not).
65	Give one test to distinguish Aniline (1∘) from N,N-Dimethylaniline (3∘).	Hinsberg's Test (Aniline gives KOH-soluble product, N,N-dimethylaniline is unreactive).

Part 6: Diazonium Salts and Synthetic Applications

Q. No.	Question	Answer
66	What are the key reagents for Diazotization?	NaNO2​ and HCl (generating HNO2​).
67	What is the required temperature for Diazotization?	0−5∘C (Diazonium salt is unstable above 5∘C).
68	What is the Diazonium group?	−N2+​ (Aryldiazonium ion).
69	Why are aromatic diazonium salts more stable than aliphatic ones?	Resonance stabilization of the diazonium ion by the benzene ring.
70	Name the reaction used to replace the -N2+​Cl− group by a -Cl or -Br group using Cu(I) salt.	Sandmeyer Reaction.
71	Name the reaction used to replace the -N2+​Cl− group by a -Cl or -Br group using Cu powder.	Gattermann Reaction.
72	What is the product when Benzene Diazonium Chloride reacts with KI?	Iodobenzene (C6​H5​I).
73	What is the product when Benzene Diazonium Chloride reacts with HBF4​ followed by heating?	Fluorobenzene (C6​H5​F) (Balz-Schiemann Reaction).
74	What is the product when Benzene Diazonium Chloride reacts with H2​O (warming)?	Phenol (C6​H5​OH) (Substitution by OH−).
75	What is the product when Benzene Diazonium Chloride is reduced with H3​PO2​?	Benzene (C6​H6​).
76	What is the characteristic reaction of diazonium salts with Phenol or Aniline?	Coupling Reaction (Formation of azo dyes).
77	What is the color of the azo dye formed by coupling Benzene Diazonium Chloride with Phenol?	Orange-yellow dye.
78	What is the color of the azo dye formed by coupling Benzene Diazonium Chloride with Aniline?	Yellow dye.
79	Which position (o, m, p) on the coupling component (Phenol/Aniline) is attacked by the diazonium ion?	Para position (due to strong activating groups).

Part 7: Final Applications and Revision

Q. No.	Question	Answer
80	What is the major product when Aniline is oxidized by Caro’s Acid (Peroxymonosulphuric Acid)?	Nitrobenzene (C6​H5​NO2​).
81	What is the role of the C-N bond cleavage in Elimination reactions of amines?	It requires the formation of a Quaternary Ammonium Salt (Hofmann Elimination).
82	What is the characteristic feature of the product of Hofmann Elimination?	Formation of the Least Substituted Alkene (Anti-Saytzeff product).
83	What is the IUPAC name for the final product of Hofmann degradation of Propanamide?	Ethylamine (CH3​CH2​NH2​).
84	Why is Acetamide (CH3​CONH2​) less basic than Methylamine (CH3​NH2​)?	The lone pair on N in Acetamide is delocalized into the C=O group by resonance.
85	Why is Benzylamine (C6​H5​CH2​NH2​) a stronger base than Aniline?	The N lone pair is not directly involved in resonance with the ring.
86	What is the common name for the reaction where Phthalic Acid is converted to Phthalimide?	Phthalimide formation (used in Gabriel Synthesis).
87	Why is the H on N in Phthalimide acidic?	The resulting anion is stabilized by resonance with two adjacent C=O groups.
88	Why are aromatic amines not generally prepared by reduction of Aryl Nitriles?	Aryl nitriles are hard to prepare (low yield).
89	Which nitrogen derivative is the most basic in the following list: Aniline,p-Nitroaniline,p-Toluidine?	p-Toluidine (-CH3​ is EDG).
90	Why does the Diazonium ion act as a weak electrophile in the coupling reaction?	The positive charge on N is delocalized by resonance with the ring.
91	What is the product when Benzene Diazonium Chloride is heated with Cu/HCl?	Chlorobenzene (C6​H5​Cl) (Gattermann reaction).
92	What is the major product when Aniline is nitrated with Conc. HNO3​/H2​SO4​?	m-Nitroaniline (due to Anilinium ion formation in acid).
93	What is the n-factor of KMnO4​ in the oxidation of an amine?	Generally 4 to 6, depending on the products (Complex Redox).
94	What is the IUPAC name for the amine used in the Hinsberg test (C6​H5​SO2​Cl)?	Benzene Sulphonyl Chloride.
95	What is the product when a 1∘ amine reacts with Aldehyde?	Schiff's Base (Imine formation, condensation).
96	What is the final fate of the CN group in the Hofmann degradation?	The C atom is lost as Na2​CO3​ (Intermediate Isocyanate).
97	What is the physical state of Aniline at room temperature?	Colorless oily liquid (turns brown on standing due to oxidation).
98	Why are 3∘ amines not used as a reagent in the Gabriel Phthalimide Synthesis?	They have no H on N to form the potassium salt.
99	How are Nitroalkanes reduced to amines (non-catalytically)?	Using Sn/HCl or Fe/HCl (Acidic Reduction).
100	What is the common catalyst used for the catalytic reduction of Nitroalkanes?	H2​/Pd or Ni (Catalytic Hydrogenation).
101	Which amine is the weakest base: p-Nitroaniline or p-Chloroaniline?	p-Nitroaniline (NO2​ is a stronger EWG).
102	What is the final product when Methylamine reacts with excess Methyl Iodide?	Quaternary Ammonium Iodide ((CH3​)4​N+I−).