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Amines

NCERT Class 12 Chemistry Chapter 9

Amines for Class 12 Chemistry, JEE and NEET: structure, preparation, basic character, tests for primary, secondary and tertiary amines, diazonium salts.

13 topics Updated 8 Nov 2026

For: Class 12, JEE and NEET, unless a topic says otherwise

In the syllabus: JEE Class 12 syllabus, NEET Class 12 syllabus

With your textbook

NCERT Chemistry Part II (Class 12), Chapter 9 “Amines”, reprint 2026-27.

Open the official NCERT chapter (PDF, 2.9 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Structure of amines

    Amines as derivatives of ammonia, the sp hybridised nitrogen, its lone pair and the pyramidal shape.

    NCERT Section 9.1 6 min read 2 solved examples 6 practice questions

  2. Classification of amines

    Primary, secondary and tertiary amines, simple and mixed amines, with NCERT’s examples.

    NCERT Section 9.2 6 min read 2 solved examples 6 practice questions

  3. Nomenclature of amines

    Common and IUPAC names, alkanamines and aniline, diamines, N-locants and the isomers of CHN.

    NCERT Section 9.3 8 min read 2 solved examples 6 practice questions

  4. Preparation of amines

    Reducing nitro compounds, nitriles and amides, ammonolysis, Gabriel synthesis and Hofmann degradation.

    NCERT Section 9.4 11 min read 3 solved examples 6 practice questions

  5. Physical properties of amines

    Odour, solubility in water, hydrogen bonding and the boiling points of 1°, 2° and 3° amines.

    NCERT Section 9.5 7 min read 2 solved examples 6 practice questions

  6. Chemical reactions of amines

    Basicity, pKb, carbylamine and Hinsberg tests, nitrous acid, bromination and nitration of aniline.

    NCERT Section 9.6 16 min read 4 solved examples 8 practice questions

  7. Experiment: tests for the amino group

    Test for amino group for JEE and NEET practical chemistry: solubility in dilute HCl, the carbylamine test and the azo dye test, and what each result shows.

    JEE and NEET only 11 min read 2 solved examples 6 practice questions

  8. Experiment: preparation of acetanilide and p-nitroacetanilide

    Acetylating aniline, nitrating below 10 °C, recrystallisation, melting points, yield.

    JEE and NEET only 13 min read 2 solved examples 6 practice questions

  9. Preparation of diazonium salts

    Diazotisation of aniline with NaNO and HCl at 273–278 K, why it is kept cold, and naming.

    NCERT Section 9.7 7 min read 2 solved examples 6 practice questions

  10. Physical properties of diazonium salts

    The colour, solubility and stability of benzenediazonium chloride and fluoroborate.

    NCERT Section 9.8 5 min read 2 solved examples 6 practice questions

  11. Chemical reactions of diazonium salts

    Sandmeyer and Gattermann reactions, replacement by I, F, H, OH and NO, and azo coupling.

    NCERT Section 9.9 10 min read 2 solved examples 6 practice questions

  12. Experiment: preparation of aniline yellow

    Diazotisation, coupling with aniline, the diazoaminobenzene route and safety.

    JEE and NEET only 11 min read 2 solved examples 6 practice questions

  13. Diazonium salts in the synthesis of aromatic compounds

    Making aryl fluorides, iodides and nitriles, removing –NH, and NCERT Example 9.5 step by step.

    NCERT Section 9.10 9 min read 2 solved examples 6 practice questions

Key formulas in this chapter

Structure of amines

  • Simple alkylamine N: sp model, 3 σ bonds + 1 lone pair, pyramidal
  • NH: H–N–H about 107°
  • (CH)N: C–N–C 108° in NCERT; measured 110.9°

Classification of amines

  • Primary: RNH (two H on N)
  • Secondary: RNH (one H on N)
  • Tertiary: RN (no H on N)
  • Quaternary ammonium salt: RNX

Nomenclature of amines

  • CHNH: methanamine (methylamine)
  • CHNHCHCH: N-methylethanamine
  • (CHCH)N: N,N-diethylethanamine
  • HN–CH–CH–NH: ethane-1,2-diamine
  • CHNH: aniline or benzenamine

Preparation of amines

  • CHNO → CHNH (H and Pd, in ethanol)
  • RNH + OH → RNH + HO (with NaOH)
  • R–C≡N → R–CH–NH (LiAlH, or H/Ni)
  • RCONH → RCHNH (LiAlH, then HO)
  • RCONH → RNH (Br + 4NaOH; one carbon less)

Physical properties of amines

  • Isomeric amines (NCERT): b.p. 1° > 2° > 3°; a trend
  • NCERT Table 9.2: alkane 300.8 K < 3° 310.5 K < 2° 329.3 K < 1° 350.8 K < alcohol 390.3 K
  • Electronegativity: N 3.0, O 3.5

Chemical reactions of amines

  • pKb = −log Kb
  • CHNH + CHCl + 3KOH → CHNC + 3KCl + 3HO (heat)
  • ArNH + NaNO + 2HCl → ArNCl + NaCl + 2HO (273–278 K)
  • CHNH + 3Br → 3HBr + CHBrNH (2,4,6-tribromoaniline)
  • Ethylamines in water: 2° > 3° > 1° > NH

Experiment: tests for the amino group

  • CHNH + H → CHNH (in dilute HCl)
  • CHNH + CHCl + 3KOH → CHNC + 3KCl + 3HO
  • ArNH + NaNO + 2HCl → ArNCl + NaCl + 2HO (0–5 °C)

Experiment: preparation of acetanilide and p-nitroacetanilide

  • CHNH + (CHCO)O → CHNHCOCH + CHCOOH
  • HNO + H → NO + HO (the H from HSO)
  • CHNHCOCH + HNO → p-ONCHNHCOCH + HO

Preparation of diazonium salts

  • ArNH + NaNO + 2HCl → ArNCl + NaCl + 2HO (273–278 K)
  • Diazonium salt: R–NX, R an aryl group

Physical properties of diazonium salts

  • CHNCl: colourless, soluble in water, unstable when warm or dry
  • CHNBF: water insoluble, stable at room temperature (NCERT); handle isolated salt with care
  • CHNCl + HO (283 K) → CHOH (phenol) + N + HCl

Chemical reactions of diazonium salts

  • ArN + I → ArI + N (with KI)
  • ArNBF (heat) → ArF + BF + N
  • ArNCl + CHOH → ArH + CHCHO + N + HCl
  • ArNCl + HO (warm) → ArOH + N + HCl
  • ArN + CHOH + OH → ArN=NCHOH + HO

Experiment: preparation of aniline yellow

  • ArNH + NaNO + 2HCl → ArNCl + NaCl + 2HO (273–278 K)
  • CHNCl + CHNH → CHN=NCHNH + HCl
  • CHN=N–NHCH → CHN=NCHNH (overall, HCl catalyst)

Diazonium salts in the synthesis of aromatic compounds

  • ArNH + NaNO + 2HCl → ArNCl + NaCl + 2HO (273–278 K)
  • ArNCl + CHOH → ArH + CHCHO + N + HCl
  • ArNBF (heat) → ArF + BF + N

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