CBSE Class 12 Chemistry Named Reactions Complete List — Reagents, Conditions, Products 2027 | Padhaao Blog

In short: CBSE Class 12 Chemistry has 30+ named reactions spread across four organic chemistry chapters — Haloalkanes & Haloarenes, Alcohols/Phenols/Ethers, Aldehydes/Ketones/Carboxylic Acids, and Amines. Named reactions carry 8–12 marks in every board paper. This post lists every single named reaction with its substrate, reagent/conditions, and product — organized chapter-wise. Mechanism summaries for key reactions (SN1, SN2, Aldol, Cannizzaro) are included at the end. Bookmark this and revise one chapter per day.

Why Named Reactions Are Non-Negotiable

Named reactions appear in almost every question type — MCQs, assertion-reason, short answers, and 5-mark organic synthesis chains. In the 2026 board paper, named reactions appeared in 4 separate questions worth a combined 11 marks. The CBSE Class 12 Chemistry chapter-wise weightage confirms that Organic Chemistry units together carry 19 marks out of 70.

Here is the complete list, organized exactly as your NCERT chapters go.

Chapter 10: Haloalkanes and Haloarenes

#	Reaction Name	Substrate	Reagent / Conditions	Product
1	Finkelstein Reaction	Alkyl chloride / bromide (R-Cl or R-Br)	NaI in dry acetone	Alkyl iodide (R-I) + NaCl/NaBr precipitate
2	Swarts Reaction	Alkyl chloride / bromide (R-Cl or R-Br)	AgF, Hg₂F₂, CoF₂, or SbF₃	Alkyl fluoride (R-F)
3	Wurtz Reaction	Alkyl halide (R-X)	2 Na, dry ether	R-R (higher alkane) + 2 NaX
4	Wurtz-Fittig Reaction	Aryl halide + Alkyl halide (Ar-X + R-X)	2 Na, dry ether	Ar-R (alkylarene)
5	Fittig Reaction	Aryl halide (Ar-X)	2 Na, dry ether	Ar-Ar (biaryl)
6	Friedel-Crafts Alkylation	Benzene (or arene)	R-Cl / Anhydrous AlCl₃	Alkylbenzene (Ar-R) + HCl
7	Friedel-Crafts Acylation	Benzene (or arene)	R-COCl / Anhydrous AlCl₃	Acylbenzene (Ar-COR) + HCl
8	Sandmeyer Reaction	Benzene diazonium salt (ArN₂⁺Cl⁻)	CuCl/HCl or CuBr/HBr or CuCN/KCN	Ar-Cl, Ar-Br, or Ar-CN
9	Gattermann Reaction	Benzene diazonium salt (ArN₂⁺Cl⁻)	Cu powder / HCl or HBr	Ar-Cl or Ar-Br
10	Balz-Schiemann Reaction	Benzene diazonium salt (ArN₂⁺Cl⁻)	HBF₄, then heat (Δ)	Ar-F + N₂ + BF₃

Key distinction: Sandmeyer uses CuX salts as catalyst; Gattermann uses Cu powder. Board examiners test this difference.

Chapter 11: Alcohols, Phenols, and Ethers

#	Reaction Name	Substrate	Reagent / Conditions	Product
11	Williamson Ether Synthesis	Sodium alkoxide (R-ONa)	Alkyl halide (R'-X), SN2 mechanism	Ether (R-O-R') + NaX
12	Kolbe's Reaction	Sodium phenoxide (C₆H₅ONa)	CO₂ at 125°C, 4–7 atm, then H₃O⁺	Salicylic acid (2-hydroxybenzoic acid)
13	Reimer-Tiemann Reaction	Phenol (C₆H₅OH)	CHCl₃ + NaOH (aq), then H₃O⁺	Salicylaldehyde (2-hydroxybenzaldehyde)
14	Reimer-Tiemann with CCl₄	Phenol (C₆H₅OH)	CCl₄ + NaOH (aq), then H₃O⁺	Salicylic acid (2-hydroxybenzoic acid)

Exam tip: Williamson synthesis works best with primary alkyl halides (SN2 path). With secondary/tertiary halides, elimination dominates — this is a frequent MCQ trap.

Chapter 12: Aldehydes, Ketones, and Carboxylic Acids

#	Reaction Name	Substrate	Reagent / Conditions	Product
15	Rosenmund Reduction	Acyl chloride (R-COCl)	H₂/Pd on BaSO₄ (poisoned catalyst), S or quinoline	Aldehyde (R-CHO)
16	Stephen Reaction	Nitrile (R-CN)	SnCl₂/HCl, then H₂O (hydrolysis)	Aldehyde (R-CHO)
17	Étard Reaction	Toluene (Ar-CH₃)	CrO₂Cl₂ in CCl₄ or CS₂	Benzaldehyde (Ar-CHO)
18	Gattermann-Koch Reaction	Benzene	CO + HCl / Anhydrous AlCl₃ + CuCl	Benzaldehyde (C₆H₅CHO)
19	Clemmensen Reduction	Aldehyde / Ketone (R-CO-R' or R-CHO)	Zn-Hg / Conc. HCl (acidic medium)	Alkane (R-CH₂-R' or R-CH₃)
20	Wolff-Kishner Reduction	Aldehyde / Ketone (R-CO-R' or R-CHO)	NH₂NH₂ (hydrazine) / KOH or NaOH, ethylene glycol, Δ (basic medium)	Alkane (R-CH₂-R' or R-CH₃)
21	Tollens' Test (Silver Mirror Test)	Aldehyde (R-CHO)	Tollens' reagent: [Ag(NH₃)₂]⁺ in NaOH	Silver mirror + R-COO⁻ (carboxylate)
22	Fehling's Test	Aldehyde (R-CHO) — aliphatic only	Fehling's A (CuSO₄) + Fehling's B (sodium potassium tartrate + NaOH)	Red precipitate of Cu₂O + R-COO⁻
23	Aldol Condensation	Aldehyde with α-hydrogen (e.g., CH₃CHO)	Dilute NaOH or KOH (base catalyst)	β-Hydroxy aldehyde (aldol), then on heating → α,β-unsaturated aldehyde
24	Cross Aldol Condensation	Two different aldehydes (one or both with α-H)	Dilute NaOH	Mixture of four products (if both have α-H)
25	Cannizzaro Reaction	Aldehyde without α-hydrogen (e.g., HCHO, C₆H₅CHO)	Conc. NaOH (strong base)	Alcohol + Sodium salt of carboxylic acid (simultaneous oxidation and reduction)
26	Kolbe Electrolysis	Sodium or potassium salt of carboxylic acid (R-COONa)	Electrolysis (aqueous solution)	R-R (alkane) at anode + CO₂ + NaOH
27	Hell-Volhard-Zelinsky (HVZ) Reaction	Carboxylic acid with α-hydrogen (R-CH₂-COOH)	Cl₂ or Br₂ / Red phosphorus (P)	α-Halocarboxylic acid (R-CHX-COOH)

Key distinction tested every year:

Clemmensen = acidic (Zn-Hg/HCl)
Wolff-Kishner = basic (NH₂NH₂/KOH)
Both convert C=O to CH₂, but the medium is opposite. Examiners love asking "which reduction works in acidic medium?"

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Chapter 13: Amines

#	Reaction Name	Substrate	Reagent / Conditions	Product
28	Gabriel Phthalimide Synthesis	Phthalimide	KOH → potassium phthalimide, then R-X (alkyl halide), then NaOH/H₂O or acid hydrolysis	Primary amine (R-NH₂) — only 1° aliphatic, NOT aromatic
29	Hoffmann Bromamide Degradation	Primary amide (R-CONH₂)	Br₂ + NaOH (or KOH)	Primary amine with one carbon less (R-NH₂) + Na₂CO₃
30	Carbylamine Reaction (Isocyanide Test)	Primary amine (R-NH₂ or Ar-NH₂)	CHCl₃ + alcoholic KOH	Isocyanide (R-NC) — foul smelling. Used as a TEST for primary amines
31	Hinsberg's Test	1°, 2°, or 3° amine	Benzenesulfonyl chloride (C₆H₅SO₂Cl) + NaOH	1° amine → soluble sulfonamide (dissolves in NaOH); 2° amine → insoluble sulfonamide; 3° amine → no reaction
32	Diazotisation	Primary aromatic amine (Ar-NH₂)	NaNO₂ + HCl at 0–5°C	Arene diazonium salt (Ar-N₂⁺Cl⁻)
33	Coupling Reaction	Arene diazonium salt (Ar-N₂⁺Cl⁻)	Phenol (in weakly basic medium) or Aniline (in weakly acidic medium)	Azo compound (Ar-N=N-Ar') — coloured dye

Gabriel synthesis limitation: It cannot prepare aromatic primary amines (Ar-NH₂) because aryl halides do not undergo SN2 with potassium phthalimide. This is tested in assertion-reason questions.

Mechanism Summaries for Key Reactions

Understanding mechanisms earns you step marks even if the final product is wrong. The board exam answer writing guide explains how examiners award partial credit for mechanism steps.

SN1 Mechanism (Substitution Nucleophilic Unimolecular)

Applies to: Tertiary alkyl halides, benzyl halides, allyl halides.

Step 1 — Ionisation (slow, rate-determining): R₃C-X → R₃C⁺ + X⁻ The carbocation forms. This is the slow step — rate depends only on substrate concentration. Rate = k[R-X]

Step 2 — Nucleophilic attack (fast): R₃C⁺ + Nu⁻ → R₃C-Nu

Key features:

Two steps, first-order kinetics
Racemisation occurs (attack from both sides of planar carbocation)
Favoured by polar protic solvents (water, ethanol)
Rearrangement of carbocation possible

SN2 Mechanism (Substitution Nucleophilic Bimolecular)

Applies to: Primary alkyl halides (best), methyl halides.

Single concerted step: Nu⁻ + R-X → [Nu---R---X]‡ → Nu-R + X⁻ Backside attack through a transition state. Rate = k[R-X][Nu⁻]

Key features:

One step, second-order kinetics
Complete inversion of configuration (Walden inversion)
Favoured by polar aprotic solvents (DMSO, acetone, DMF)
No rearrangement possible
Steric hindrance slows it: CH₃X > 1° > 2° >> 3° (too slow)

Aldol Condensation Mechanism

Step 1 — Formation of enolate ion: CH₃CHO + OH⁻ → ⁻CH₂CHO + H₂O (Base abstracts α-hydrogen to form carbanion/enolate)

Step 2 — Nucleophilic addition: ⁻CH₂CHO + CH₃CHO → CH₃CH(OH)CH₂CHO (aldol — β-hydroxy aldehyde)

Step 3 — Dehydration on heating: CH₃CH(OH)CH₂CHO → CH₃CH=CHCHO + H₂O (α,β-unsaturated aldehyde — crotonaldehyde)

Board marking: Examiners give 1 mark for enolate formation, 1 mark for addition, 1 mark for product with correct name. If you skip the enolate step, you lose 1 mark.

Cannizzaro Reaction Mechanism

Applies to: Aldehydes WITHOUT α-hydrogen (HCHO, C₆H₅CHO, (CH₃)₃CCHO).

Step 1 — Nucleophilic addition of OH⁻: Ar-CHO + OH⁻ → Ar-CH(OH)(O⁻) (tetrahedral intermediate)

Step 2 — Hydride transfer: Ar-CH(OH)(O⁻) + Ar-CHO → Ar-COO⁻ + Ar-CH₂OH One molecule is oxidized to carboxylate; another is reduced to alcohol.

Board marking: 1 mark for identifying "no α-hydrogen" condition, 1 mark for hydride transfer step, 1 mark for both products (acid salt + alcohol).

Quick-Revision Table: Reaction → Reagent Trigger Words

When reading a board question, look for these reagent keywords to instantly identify the named reaction:

Reagent / Condition in Question	Named Reaction
NaI / dry acetone	Finkelstein
AgF or SbF₃	Swarts
Na / dry ether (alkyl halides)	Wurtz
CHCl₃ + NaOH + phenol	Reimer-Tiemann
CO₂ + NaOH + phenol	Kolbe's
H₂ / Pd-BaSO₄ (poisoned)	Rosenmund
SnCl₂ / HCl on nitrile	Stephen
Zn-Hg / conc. HCl	Clemmensen
NH₂NH₂ / KOH, Δ	Wolff-Kishner
Dilute NaOH + aldehyde with α-H	Aldol
Conc. NaOH + aldehyde without α-H	Cannizzaro
Br₂ / Red P + carboxylic acid	HVZ
Br₂ + NaOH + amide	Hoffmann Bromamide
CHCl₃ + alc. KOH + amine	Carbylamine
NaNO₂ + HCl, 0–5°C	Diazotisation
CuCl/HCl or CuBr/HBr + diazonium salt	Sandmeyer
C₆H₅SO₂Cl + NaOH + amine	Hinsberg's Test

This table alone can help you attempt 3–4 MCQs in under 2 minutes. For more on solving MCQs quickly, see how to study chemistry: organic, inorganic, physical.

Chapter-Wise Marks Contribution of Named Reactions

Chapter	Approximate Named Reactions	Typical Board Marks
Haloalkanes & Haloarenes (Ch 10)	10 reactions	3–4 marks
Alcohols, Phenols, Ethers (Ch 11)	4 reactions	2–3 marks
Aldehydes, Ketones, Carboxylic Acids (Ch 12)	13 reactions	4–5 marks
Amines (Ch 13)	6 reactions	2–3 marks
Total	33 reactions	11–15 marks

That's roughly 16–21% of the theory paper from named reactions alone. Combined with the full chemistry chapter-wise weightage, this makes Organic Chemistry the most marks-dense section.

How to Memorize 33 Named Reactions

Day 1: Learn Haloalkane reactions (10 reactions). Write each reaction 3 times.
Day 2: Learn Alcohol/Phenol reactions (4 reactions). Revise Day 1 reactions once.
Day 3: Learn Aldehyde/Ketone reactions (13 reactions). Write mechanism for Aldol and Cannizzaro.
Day 4: Learn Amine reactions (6 reactions). Revise all previous.
Day 5: Full test — write all 33 reactions from memory without looking.
Day 6 onward: Write 10 random reactions daily until the exam.

This 5-day cycle works because you are using spaced repetition. For the science behind this, check out how to study smart, not hard.

Common Board Exam Mistakes With Named Reactions

Mistake	Why It Loses Marks
Writing "Na" instead of "NaI in dry acetone" for Finkelstein	Missing reagent condition — 0.5 marks lost
Confusing Sandmeyer and Gattermann	CuX salt vs Cu powder distinction — full 1 mark lost
Forgetting "poisoned catalyst" in Rosenmund	Without BaSO₄ poison, further reduction to alcohol occurs — 0.5 marks
Not writing α-hydrogen condition for Aldol	Examiner expects "aldehydes having α-hydrogen" — 1 mark
Gabriel synthesis with ArX	Gabriel CANNOT make aromatic amines — full marks lost if wrong product
Writing wrong medium for Clemmensen vs Wolff-Kishner	Acidic vs basic — tested every single year

Frequently Asked Questions

How many named reactions are there in CBSE Class 12 Chemistry?

There are 33 named reactions across four chapters of Organic Chemistry (Chapters 10–13). These include 10 reactions in Haloalkanes, 4 in Alcohols/Phenols, 13 in Aldehydes/Ketones/Acids, and 6 in Amines. Every reaction listed in NCERT is fair game for the board exam.

Which named reactions are most frequently asked in CBSE board exams?

Based on analysis of papers from 2019–2026, the most frequently tested are: Aldol condensation, Cannizzaro reaction, Sandmeyer reaction, Williamson synthesis, Clemmensen vs Wolff-Kishner reduction, Gabriel phthalimide synthesis, and Hoffmann bromamide degradation. At least 3–4 of these appear every year.

Do I need to write mechanisms for named reactions in the board exam?

Yes, for 3-mark and 5-mark questions. The CBSE marking scheme awards step marks for mechanism — especially for SN1, SN2, Aldol condensation, and Cannizzaro reaction. Even if your final product is wrong, correct mechanism steps earn partial marks.

What is the difference between Clemmensen and Wolff-Kishner reduction?

Both convert C=O (carbonyl) to CH₂ (methylene). Clemmensen uses Zn-Hg in concentrated HCl (acidic conditions), while Wolff-Kishner uses hydrazine (NH₂NH₂) with KOH in ethylene glycol at high temperature (basic conditions). They produce the same product but in opposite pH environments.

Can Tollens' test distinguish between aldehydes and ketones?

Yes. Tollens' reagent ([Ag(NH₃)₂]⁺) gives a positive silver mirror test only with aldehydes, not with ketones. This is because aldehydes are easily oxidized to carboxylic acids while ketones resist oxidation. Fehling's test also works but only for aliphatic aldehydes (aromatic aldehydes like benzaldehyde give a negative Fehling's test).

How should I write named reactions in the board exam for full marks?

Write in this order: (1) Substrate with structural formula, (2) Reagent and conditions written above and below the arrow, (3) Product with structural formula, (4) Name of the reaction. For mechanism questions, show each step separately with curved arrows and label the intermediates. Using the answer sheet formatting guide can help you present reactions clearly.

CBSE Class 12 Chemistry Named Reactions Complete List — Reagents, Conditions, Products 2027