With the CBSE Class 12 Chemistry board exam scheduled for February 27, 2026, Organic Chemistry is once again emerging as the section that can make or break scores. Nearly 28 marks are directly linked to Organic chapters such as Alcohols, Aldehydes, Ketones, Carboxylic Acids, and Amines. For students also preparing for JEE, the overlap is even more critical, as reaction mechanisms alone carry close to 20 percent weightage in entrance exams.
The challenge is not lack of content but overload. Organic Chemistry becomes confusing when reactions are memorised in isolation. That is why flowchart-based learning works. When reactions are grouped by functional class and reagent logic, nearly 70 percent of the syllabus turns into predictable conversion pathways rather than random equations.
This guide brings together 30 high-frequency named reactions arranged as visual flows, exactly the way CBSE questions are framed.
How CBSE tests Organic Chemistry
CBSE rarely asks obscure reactions. Most questions follow a pattern:
-
Identify the functional group
-
Apply the correct reagent
-
Predict the product or intermediate
In recent board papers, conversion-based questions and reasoning-based name reactions together account for more marks than straight definitions. Students who understand reaction direction and conditions score faster and cleaner.
Haloalkanes and Haloarenes (4 Marks)
These reactions form the entry point of Organic Chemistry conversions and often appear as one-step questions.
Swarts Reaction
Alkyl chloride converts to alkyl fluoride using silver fluoride.
Think of it as halogen replacement under heat.
Wurtz Reaction
Two alkyl halides combine using sodium in dry ether to form a higher alkane.
This reaction tests carbon chain coupling logic.
Sandmeyer Reaction
Diazonium salts transform into haloarenes using copper salts.
This reaction connects Amines to Aromatic substitutions.
Alcohols, Phenols, and Ethers (12 Marks)
This is the most important block for CBSE 2026.
Williamson Ether Synthesis
Alcohol to ether via sodium alkoxide and alkyl halide.
Appears frequently in conversion chains.
Lucas Test
Distinguishes primary, secondary, and tertiary alcohols based on reaction speed.
Cloudiness timing is the scoring point.
Reimer–Tiemann Reaction
Phenol converts to salicylaldehyde using chloroform and NaOH.
Expect direct name reaction or reasoning questions.
Carbonyl Compounds and Carboxylic Acids (8 Marks)
This section dominates long-answer questions.
Aldol Condensation
Aldehydes with alpha hydrogen form beta-hydroxy compounds, then dehydrate on heating.
CBSE loves this reaction with mechanism arrows.
Cannizzaro Reaction
Aldehydes without alpha hydrogen disproportionate into alcohol and acid.
Common trap: students forget the alpha-hydrogen condition.
Haloform Reaction
Methyl ketones produce yellow iodoform precipitate.
This is a classic test-based question.
Rosenmund Reduction
Acid chlorides reduce selectively to aldehydes using poisoned catalysts.
Used in multi-step conversions.
Stephen Reaction
Nitriles convert to aldehydes via imine intermediates.
Important for reaction logic questions.
Amines (4 Marks)
Short but high-scoring.
Hoffmann Bromamide Reaction
Amides convert to amines with one carbon less.
This reaction tests structural change awareness.
Carbylamine Reaction
Primary amines form foul-smelling isocyanides.
Used as a confirmatory test.
Hinsberg Test
Distinguishes primary, secondary, and tertiary amines based on solubility behavior.
Aromatic Substitution and Phenol Reactions
These reactions test reagent selection rather than memorisation.
Nitration and Sulphonation
Electrophilic substitution using mixed acids or oleum.
Friedel–Crafts Alkylation
Introduces alkyl groups into benzene rings using Lewis acids.
Kolbe–Schmitt Reaction
Phenol converts to salicylic acid under pressure and heat.
A guaranteed board favourite.
Diazonium Salt Conversions (6 Marks)
Diazonium chemistry bridges Amines and Aromatic compounds.
Sandmeyer and Gatterman Reactions
Replace diazonium groups with halogens.
Balz–Schiemann Reaction
Only reliable method to introduce fluorine into aromatic rings.
Oxidation and Reduction Essentials
Jones Oxidation
Primary alcohols oxidise to carboxylic acids using chromium reagents.
CBSE checks reagent-condition clarity here.
10-Day Smart Revision Plan Before the Exam
Days 1–3
Haloalkane to Alcohol to Carbonyl conversions
Days 4–6
Aromatic substitutions and Diazonium reactions
Days 7–8
Solve previous year questions from 2020–2025
Days 9–10
Full-length mock tests with error analysis
Boards reward pattern recognition, not brute memorisation.
Common Mistakes Students Must Avoid
Confusing hot and cold oxidation conditions
Mixing up named reaction spellings
Ignoring reaction conditions while writing products
Overthinking stereochemistry, which CBSE rarely tests
Final Thoughts For Student
Organic Chemistry becomes manageable once reactions are seen as pathways rather than pages of equations. If you can mentally move from one functional group to another using the correct reagent, you already control most of the syllabus. Boards reward clarity and structure, not volume.
