Top 40 Organic Chemistry Reactions You Must Master for NEET 2027

Why Organic Chemistry Reactions Are Important for NEET 2027?

Organic Chemistry includes a lot of organic reactions, be it named reactions, identification of products, or reactions involving reagents. Without knowing the underlying reactions, it becomes really difficult to predict the correct answer.

Learning these organic reactions also improves conceptual clarity and understanding regarding the reaction mechanisms. Apart from this, organic reactions also help build speed and accuracy required during the exam, as many important NEET questions can be solved quickly if the students become familiar with the common reactions and reagents.

Top 40 reactions every aspirant should know

To score well in the NEET organic chemistry section, rather than studying and wasting time on random reactions, it's always better to focus on the most important and frequently asked reactions.

Below are 40 important organic Chemistry reactions that every NEET aspirant should study:

Hydrocarbon Reactions

Hydrocarbon reactions mainly involve substitution reactions that help in converting simple hydrocarbons into more complex compounds.

Here are a few important Hydrocarbon reactions:

1. Free Radicals in Halogenation

In halogenation reactions by free radicals, hydrogen in alkanes is replaced by a halogen such as chlorine and bromine with the help of light as the catalyst.

2. Wurtz Reaction

This reaction involves the formation of large hydrocarbons from two different alkyl groups joined together with the help of sodium in dry ether.

3. Wurtz–Fittig Reaction

In this reaction, an alkyl halide reacts with an aryl halide to form an alkyl-substituted aromatic compound.

4. Kolbe’s Electrolysis

It is an electrochemical reaction that includes the electrolysis of the salts of carboxylic acids to form hydrocarbons by the coupling of alkyl groups.

5. Fittig Reaction

Fittig reaction joins two aromatic halides together in the presence of sodium metal, which results in the production of a larger aromatic compound.

Alkene and Alkyne Reactions

Both alkenes and alkynes are unsaturated hydrocarbons that contain double and triple bonds. This is the reason why they are more reactive than alkanes and can undergo a variety of addition and oxidation reactions.

Some of which are:

6. Hydroboration–Oxidation

It is a type of reaction that includes the conversion of alkenes into alcohols, where the hydroxyl group attaches to the carbon that is less substituted.

7. Ozonolysis

Ozone in this reaction helps in breaking the double bond of alkenes, which leads to the production of smaller carbonyl compounds like aldehydes or ketones.

In the same manner, here are a few other Alkene and Alkyne reactions which are important from the point of view of the NEET exam:

8. Markovnikov Addition

In this type of reaction, in an unsymmetrical alkene, hydrogen adds to the carbon already having more hydrogens, and the other group adds to the carbon with fewer hydrogens.

9. Anti-Markovnikov Addition

Anti-markonikov addition is simply an unsymmetrical alkene, hydrogen adds to the carbon with fewer hydrogens, and the other group adds to the carbon with more hydrogens.

10. Baeyer’s Test

This test is used mainly for unsaturated compounds.

11. Lindlar Catalyst Reduction

In this reaction, an alkyne is partially reduced to a cis-alkene by the help of a poisoned Pd catalyst.

12. Birch Reduction

It is a type of reduction where an aromatic ring is reduced with the help of sodium in liquid ammonia in the presence of alcohol.

Alcohol, Phenol, and Ether Reactions

Alcohols, phenols, and ethers are the functional groups in organic chemistry that appear frequently in NEET chemistry questions.

Some of the most important reactions involving these functional groups are given below

13. Lucas Test

It is a qualitative test to distinguish between primary, secondary, and tertiary alcohols.

14. Williamson Ether Synthesis

A method for preparing ethers by reacting an alkoxide ion with an alkyl halide.

16. Reimer–Tiemann Reaction

Reaction used to introduce an aldehyde group into a phenol ring, producing aromatic aldehydes.

17. Acid Catalyzed Dehydration of Alcohol

Acid-catalyzed dehydration of alcohol reaction.

Aldehyde and Ketone Reactions

Aldehydes and ketones are the functional groups that make the organic compound undergo various oxidation, reduction, and addition reactions.

18. Aldol Condensation

Aldehydes or ketones combine to form larger molecules containing both alcohol and carbonyl functional groups

19. Cannizzaro Reaction

Aldehyde undergoes self-oxidation and reduction simultaneously to give out alcohol and carboxylic acid.

20. Clemmensen Reduction

Conversion of aldehydes or ketones into hydrocarbons with the help of strong acidic conditions.

21. Wolff–Kishner Reduction

It is a type of reaction which involves the reduction of a carbonyl compound to an alkane using hydrazine in the presence of a strong base like KOH at high temperature.

22. Haloform Reaction

The reaction between methyl ketones, halogen and a base to give holoform along with a carboxylate salt as a product.

23. Tollens’ Test

Tollen's test is used for aldehydes, while the ketones do not react to the reagent which is used during this test.

24. Fehling’s Test

This test is mainly used for testing the presence of aliphatic aldehydes.

25. Benzoin Condensation

Benzoin condensation is basically when two Molecules of aromatic aldehyde condense in the presence of CN negative to form benzoin, which is an alpha-hydroxy ketone.

26. Perkin Reaction

An aromatic aldehyde reacts with an acid anhydride in the presence of a base like sodium acetate to give an alpha, beta-unsaturated aromatic acid.

Carboxylic Acid Reactions

Carboxylic Acids are organic compounds that contain the carboxyl functional group.

27. Hell–Volhard–Zelinsky Reaction

Introduction of a halogen atom at the carbon next to the carboxylic acid group.

28. Soda Lime Reaction

In this reaction, the formation of hydrocarbons takes place after the carboxylic acid loses carbon dioxide.

29. Fischer Esterification

Carboxylic acid reacts with alcohol in the presence of an acid to form esters and water.

Amine Reactions

Amines are those organic compounds that are derived from ammonia, in which one or more hydrogen atoms are replaced by alkyl or aryl groups.

30. Gabriel Phthalimide Synthesis

It is a reaction which involves the preparation of primary amines by the reaction of phthalimide with alkyl halides.

31. Hofmann Bromamide Degradation

In this reaction, an amide is converted into a primary amine with one carbon less using bromine and a base such as KOH or NaOH.

32. Carbylamine Reaction

Here, Primary amines react with chloroform and alcoholic KOH to form the foul-smelling isocyanides.

33. Hinsberg Test

This test is basically used for distinguishing between the primary, secondary and tertiary amines based mainly on their reaction with Hinsberg reagent.

Aromatic Substitution Reactions

Aromatic compounds are organic molecules that contain a stable ring structure with delocalized electrons. For example, benzene.

34. Friedel–Crafts Alkylation

In this reaction, an aromatic ring reacts with an alkyl halide in the presence of a Lewis acid to give an alkyl substituted aromatic compound as the product.

35. Friedel–Crafts Acylation

Here, an aromatic ring undergoes reaction with an acyl chloride or an acid anhydride in the presence of a Lewis acid to form a ketone.

36. Nitration of Benzene

In this type of reaction, the benzene reacts with conc. nitric acid in the presence of sulfuric acid to form nitrobenzene.

37. Sulphonation of Benzene

It is a reaction between benzene and fuming sulfuric acid to form benzene sulfonic acid.

38. Halogenation of Benzene

The benzene reacts with a halogen in the presence of a lewis acid to form halobenzene.

Diazonium Salt Reactions

Diazonium salts are organic compounds that are highly reactive. These are formed from aromatic amines.

39. Sandmeyer Reaction

Diazonium salts are converted into substituted aromatic compounds using copper salts.

40. Gattermann Reaction

This reaction is used to introduce halogen or other groups into aromatic rings in the presence of a catalyst.

How to Memorise Organic Reactions for NEET 2027?

Many aspirants fail to understand organic chemistry because instead of understanding, they try to memorise all concepts and reactions. Only a planned approach can help retain reactions for a longer time and improve accuracy in exams.

Here are a few pointers that can help aspirants memorise the reactions in an effective way:

1. Focus on understanding the purpose of each reaction rather than memorising it blindly.

2. Learn the reagents and conditions.

3. Practice conversion questions that combine multiple reactions.

4. Revise reactions regularly using short notes or flashcards.

5. Solve the previous year NEET questions related to these reactions.

Following these instructions and maintaining a consistent revision and practice regime will surely help students in scoring good marks in NEET Organic Chemistry.