Class 12 Organic Chemistry: Named Reactions You Must Know for Boards
A quick-revision list of high-yield named reactions from Class 12 organic chemistry — what they do and where they are used.
Why revise these: Named reactions are frequent, high-scoring board questions. Learn the reagent, the transformation and one example for each — that is usually enough to answer confidently.
High-yield named reactions
| Reaction | What it does | Key reagent |
|---|---|---|
| Cannizzaro | Aldehydes with no α-H disproportionate to alcohol + acid salt | Conc. NaOH |
| Aldol condensation | Aldehydes/ketones with α-H form β-hydroxy carbonyl, then α,β-unsaturated | Dilute base |
| Rosenmund reduction | Acyl chloride → aldehyde | H₂/Pd-BaSO₄ |
| Hofmann bromamide | Amide → primary amine (one C less) | Br₂ + NaOH |
| Sandmeyer | Diazonium salt → aryl halide | CuCl/CuBr |
| Reimer–Tiemann | Phenol → salicylaldehyde | CHCl₃ + NaOH |
How to revise them fast
- Group by product type (amine-forming, aldehyde-forming, C–C bond-forming).
- Write the general equation once, then one specific example.
- Note the exam “trigger” — e.g. “no α-hydrogen” points to Cannizzaro.
Frequently tested points
- Which aldehydes give Cannizzaro vs aldol (presence/absence of α-H).
- Product with one carbon less → Hofmann bromamide.
- Selective reduction of acyl chloride to aldehyde → Rosenmund.
FAQs
How many named reactions come in Class 12 boards?
Several appear across aldehydes/ketones, amines and haloarenes. Confirm emphasis from the current CBSE/ISC syllabus and past papers.
Do I need mechanisms?
For boards, the transformation and reagent usually suffice; mechanisms help for JEE/NEET.
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