NCERT Solutions Class 12 Chemistry Chapter 13

NCERT Solutions Class 12 Chemistry Chapter 13 Amines

This chapter emphasises the importance of ‘Amines’ as ‘Ammonia’ derivatives with a Pyramidal structure. You will learn about some of the essential amine preparation methods. This also gives you a good idea of what their chemical properties are.

In addition, you will learn about diazonium salts and how to make them in this Chapter. This will also help you comprehend the significance of these salts in aromatic compound production. Finally, answering the NCERT questions from Chapter 13 will help you dispel any remaining doubts you may have about the relevant topics.

NCERT Solutions Class 12 Chemistry Chapter 13 – Amines will help you comprehend the ideas of amines to retain complex amine structural formulas and imprint them on your memory for a long time. 

NCERT Solutions Class 12 Chemistry Chapter 13 were developed by subject specialists at Extramarks using the most recent term – II CBSE Syllabus and its standards. Any doubts about the Chapter can be quickly resolved by consulting and preparing for your Examinations with these solutions.

To prepare well for the second term Examinations, students should practise these NCERT Solutions For Class 12 Chemistry Chapter 13 daily. Here you will find worksheets, exercises, sample problems, HOTS (Higher Order Thinking Skills), and assignments to help you ace the ‘Amines’. You can access the NCERT Solutions Class 12 Chemistry Chapter 13 by clicking below listed links.

Key Topics Covered in NCERT Solutions Class 12 Chemistry Chapter 13

Students will be able to comprehend the nomenclature, properties, and structure of amines using the Class 12 NCERT Solutions for this Chapter. The most critical nitrogen-containing organic molecules are amines. Our subject experts thoroughly explain solved cases based on the basicity of amines, synthesis, and reactions that amines undergo.

NCERT Solutions Class 12 Chemistry Chapter 13 Amines contains topics and subtopics that will aid you in your overall CBSE Class 12 Chemistry preparation. NCERT Solutions For Class 12 Chemistry Chapter 13 access links have a total of ten topics and exercises:

Ex. 13.1: Structure of Amines

Ex. 13.2: Classification

Ex. 13.3: Nomenclature

Ex. 13.4: Preparation of Amines

Ex. 13.5: Physical Properties

Ex. 13.6: Chemical Reactions

Ex. 13.7: Method for the Preparation of Diazonium Salts

Ex. 13.8: Physical Properties

Ex. 13.9: Chemical Reactions

Ex. 13.10: Importance of Diazonium Salts in the Synthesis of Aromatic Compounds

NCERT Solutions Class 12 Chemistry Chapter 13: Marks Weightage

Very short answer (1 mark) Short answer (3 marks) Total Marks
                          1                         3                           4

Even though this Chapter receives fewer marks, Extramarks recommend students not overlook it.

NCERT Solutions Class 12 Chemistry Chapter 13: Exercises & Answers

Students can access the NCERT Solutions Class 12 Chemistry Chapter 13 from the links below. Students can access these solutions at any time. Extramarks solutions adhere to all NCERT rules, which will help you cover everything you may get asked for from this Chapter. We’ve included some examples below to show you how we solved these Chemistry Chapter 13 NCERT questions.

The answer sets are created by a team of professionals familiar with the CBSE Board marking structure and Examination format. Students can use these solution sets to learn how to approach a problem and drastically improve their scores. So keep scrolling down the page to get the Class 12 Chemistry Chapter 13 NCERT Solutions from the links below.

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.1

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.2

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.3

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.4

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.5

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.6

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.7

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.8

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.9

NCERT Solutions Class 12 Chemistry Chapter 13 Ex 13.10

Few Important Questions from Class 12 Chemistry Chapter 13

  • Convert Ethanoic acid to methylamine and Propanoic acid to ethanoic acid
  • How do identify primary, secondary, tertiary amines? Write the reactions involved.
  • Is it possible to prepare primary aromatic amines by Gabriel phthalimide synthesis? Why?
  • Which of the two has a higher boiling point, primary amines or tertiary amines? Why?
  • Which among the following is a strong base: Aliphatic amines or Aromatic amines? Explain with a valid reason.
  • Explain Hofmann’s bromamide reaction.
  • Distinguish between Methylamine and Dimethylamine with a chemical test.

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Advantages of NCERT Solutions Class 12 Chemistry Chapter 13

Following are some of the pros of the NCERT Solutions Class 12 Chemistry Chapter 13-Amines.

  • A language that is simple to comprehend.
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Students should visit the Extramarks website and use the NCERT Solutions Class 12 Chapter 13: Amines to understand better the topics involved. Students perform well on their tests because of the considerable knowledge they learn from these NCERT Solutions.

NCERT Exemplar Class 12 Chemistry

NCERT Exemplars are practice books with additional higher-level problems that are designed to help students learn more thoroughly. They are primarily used in competitive Examinations. The Exemplar material is current and includes various topics discussed in each Chapter of the NCERT Solutions Class 12 Chemistry Chapter 13. 

Students can get these Exemplar questions and answers for Class 12 Chemistry Chapter-by-Chapter notes by clicking on the Extramarks links.

Practising Exemplar problems is necessary for school Boards and competitive Examinations because of the high standard and variety. Students can assess themselves ideally by working on these questions and improving their problem-solving skills for future Examinations. NCERT Solutions Class 12 Chemistry Chapter 13 prepared by Extramarks is a set of example solutions for Class 12 Chemistry Chapter 13 that includes extensive explanations for all of the questions in the NCERT Exemplar Class 12 books.

Q.1 Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.

(i) (CH3)2CHNH2 (ii) CH3(CH2)2NH2
(iii) CH3NHCH(CH3)2 (iv) (CH3)3CNH2
(v) C6H5NHCH3 (vi) (CH3CH2)2NCH3
(vii) m-BrC6H4NH2


(i) 1-Methylethanamine (10 amine)

(ii) Propan-1-amine (10 amine)

(iii) N-Methyl-2-methylethanamine (20 amine)

(iv) 2-Methylpropan-2-amine (10 amine)

(v) N-Methylbenzamine or N-methylaniline (20 amine)

(vi) N-Ethyl-N-methylethanamine (30 amine)

(vii) 3-Bromobenzenamine or 3-bromoaniline (10 amine)

Q.2 Give one chemical test to distinguish between the following pairs of compounds.

(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylaniline.


(i) Methylamine and dimethylamine can be distinguished by the carbylamine test. Carbylamine test: Aliphatic and aromatic primary amines on heating with chloroform and ethanolic potassium hydroxide form foul-smelling isocyanides or carbylamines. Methylamine (being an aliphatic primary amine) gives a positive carbylamine test, but dimethylamine does not.

CH 3 NH 2 + CHCl 3 Methylamine( ) +3KOH Δ CH 3 NC+3KCl Methylisocyanide ( foulsmell ) + 3H 2 ( CH 3 ) 2 NH+ CHCl 3 +3KOH Δ Noreaction MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@B736@

(ii) Secondary and tertiary amines can be distinguished by allowing them to react with Hinsberg’s reagent (benzenesulphonyl chloride, C6H5SO2Cl).

Secondary amines react with Hinsberg’s reagent to form a product that is insoluble in an alkali. For example, N, N-diethylamine reacts with Hinsberg’s reagent to form N, N-diethylbenzenesulphonamide, which is insoluble in an alkali. Tertiary amines, however, do not react with Hinsberg’s reagent.

(iii) Ethylamine and aniline can be distinguished using the azo-dye test. A dye is obtained when aromatic amines react with HNO2 (NaNO2 + dil.HCl) at 0-5°C, followed by a reaction with the alkaline Solution of 2-naphthol. The dye is usually yellow, red, or orange in colour. Aliphatic amines give a brisk effervescence due (to the evolution of N2 gas) under similar conditions.

(iv) Aniline and benzylamine can be distinguished by their reactions with the help of nitrous acid, which is prepared in situ from a mineral acid and sodium nitrite. Benzylamine reacts with nitrous acid to form unstable diazonium salt, which in turn gives alcohol with the evolution of nitrogen gas.

On the other hand, aniline reacts with HNO2 at a low temperature to form stable diazonium salt. Thus, nitrogen gas is not evolved.

C 6 H 5 NH 2 273278K NaNO 2 +HCl C 6 H 5 N + 2 C l +NaCl+ 2H 2 O MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@7125@

(v) Aniline and N-methylaniline can be distinguished using the Carbylamine test. Primary amines, on heating with chloroform and ethanolic potassium hydroxide, form foul- smelling isocyanides or carbylamines. Aniline, being an aromatic primary amine, gives positive carbylamine test. However, N-methylaniline, being a secondary amine does not.

Q.3 Account for the following:

(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
(iv) Although amino group is o, p- directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines.
(vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.


(i) pKb of aniline is more than that of methylamine:

Aniline undergoes resonance and as a result, the electrons on the N-atom are delocalized over the benzene ring. Therefore, the electrons on the N-atom are less available to donate.

On the other hand, in case of methylamine (due to the +I effect of methyl group), the electron density on the N-atom is increased. As a result, aniline is less basic than methylamine.

Thus, pKb of aniline is more than that of methylamine.

(ii) Ethylamine is soluble in water whereas aniline is not:

Ethylamine when added to water forms intermolecular H-bonds with water. Hence, it is soluble in water.

But aniline does not undergo H-bonding with water to a very large extent due to the presence of a large hydrophobic -C6H 5 group. Hence, aniline is insoluble in water.

(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide:

Due to the +I effect of -CH3 group, methylamine is more basic than water. Therefore, in water, methylamine produces OH ions by accepting H+ ions from water

CH 3 NH 2 +HOH CH 3 NH 3 + OH MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeaacaGaaiaabeqaamaabaabaaGcbaGaae4qaiaabIeadaWgaaWcbaGaae4maaqabaGccaaMc8Uaae4eGiaaykW7caqGobGaaeisamaaBaaaleaacaqGYaaabeaakiaaykW7caqGRaGaaGPaVlaabIeacaaMc8Uaae4eGiaaykW7caqGpbGaaeisaiaaykW7daGdKaWcbaaabeGccaGLsgcacaaMc8Uaae4qaiaabIeadaWgaaWcbaGaae4maaqabaGccaaMc8Uaae4eGiaaykW7caqGobGaaeisamaaBaaaleaacaqGZaaabeaakiaaykW7caqGRaGaaGPaVlaab+eacaqGibWaaWbaaSqabeaacaqGTaaaaaaa@5EB6@

Ferric chloride (FeCl3) dissociates in water to form Fe3+ and Cl ions.

FeCl 3 Fe 3+ + 3Cl MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeaacaGaaiaabeqaamaabaabaaGcbaGaaeOraiaabwgacaqGdbGaaeiBamaaBaaaleaacaqGZaaabeaakiaaykW7daGdKaWcbaaabeGccaGLsgcacaaMc8UaaeOraiaabwgadaahaaWcbeqaaiaabodacaqGRaaaaOGaaGPaVlaabUcacaaMc8Uaae4maiaaboeacaqGSbWaaWbaaSqabeaacaqGtacaaaaa@4B8F@

Then, OH ion reacts with Fe3+ ion to form a precipitate of hydrated ferric oxide.

2Fe 3+ + 6OH Fe 2 O 3 . 33H 2 O Hydrated ferricoxide MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@68CE@

(iv) Although amino group is o,p- directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m- nitroaniline: Nitration is carried out in an acidic medium. In an acidic medium, aniline is protonated to give anilinium ion (which is meta-directing).

For this reason, aniline on nitration gives a substantial amount of m-nitroaniline.

(v) Aniline does not undergo Friedel-Crafts reaction: A Friedel-Crafts reaction is carried out in the presence of AlCl3. But AlCl 3 is acidic in nature, while aniline is a strong base. Thus, aniline reacts with AlCl3 to form a salt (as shown in the following equation).

Due to the positive charge on the N-atom, electrophilic substitution in the benzene ring is deactivated. Hence, aniline does not undergo the Friedel-Crafts reaction.

(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines: The diazonium ion undergoes resonance as shown below:

This resonance accounts for the stability of the diazonium ion. Hence, diazonium salts of aromatic amines are more stable than those of aliphatic amines.

(vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines: Gabriel phthalimide synthesis results in the formation of 1° amine only. 2° or 3° amines are not formed in this synthesis. Thus, a pure 1° amine can be obtained. Therefore, Gabriel phthalimide synthesis is preferred for synthesizing primary amines.

Q.4 Arrange the following:
(i) In decreasing order of the pKbvalues:
C2H5NH2, C6H5NHCH3, (C2H5)2NH and C6H5NH2

(ii) In increasing order of basic strength:
C6H5NH2, C6H5N(CH3)2, (C2H5)2NH and CH3NH2

(iii) In increasing order of basic strength:
Aniline, p-nitroaniline and p-toluidine

(iv) In decreasing order of basic strength in gas phase:
C2H5NH2, (C2H5)2NH, (C2H5)3N and NH3

(v) In increasing order of boiling point:
C2H5OH, (CH3)2NH, C2H5NH2

(vi) In increasing order of solubility in water:
C6H5NH2, (C2H5)2NH, C2H5NH2.


(i) In C2H5NH2, only one -C2H5 group is present while in (C2H5)2NH, two -C2H5 groups are present. Thus, the +I effect is more in (C2H5)2NH than in C2H5NH2. Therefore, the electron density over the N-atom is more in (C2H5)2NH than in C2H5NH2. Hence, (C2H5)2NH is more basic than C2H5NH2.

Also, both C6H5NHCH3 and C6H5NH2 are less basic than (C2H5)2NH and C2H5NH2 due to the delocalization of the lone pair in the former two. Further, among C6H5NHCH3 and C6H5NH2, the former will be more basic due to the +I effect of -CH3 group. Hence, the order of increasing basicity of the given compounds is as follows:

C6H5NH2 < C6H5NHCH3 < C2H5NH2 < (C2H5)2NH

We know that the higher the basic strength, the lower is the pKb values.

C6H5NH2 > C6H5NHCH3 > C2H5NH2 > (C2H5)2NH

(ii) C6H5N(CH3)2 is more basic than C6H5NH2 due to the presence of the +I effect of two -CH3 groups in C6H5N(CH3)2. Further, CH3NH2 contains one -CH3 group while (C2H5)2NH contains two -C2H5 groups. Thus, (C2H5)2NH is more basic than C2H5NH2.

Now, C6H5N(CH3)2 is less basic than CH3NH2 because of the-R effect of -C6H5 group. Hence, the increasing order of the basic strengths of the given compounds is as follows:

C6H5NH2 < C6H5N(CH3)2 < CH3NH2 < (C2H5)2NH

(iii) (a)

In p-toluidine, the presence of electron-donating -CH3 group increases the electron density on the N-atom.

Thus, p-toluidine is more basic than aniline.

On the other hand, the presence of electron-withdrawing

-NO2 group decreases the electron density over the N-atom in p-nitroaniline. Thus, p- nitroaniline is less basic than aniline.

Hence, the increasing order of the basic strengths of the given compounds is as follows:

p-Nitroaniline < Aniline < p-Toluidine

(b) C6H5NHCH3 is more basic than C6H5NH2 due to the presence of electron-donating -CH3 group in C6H5NHCH3.

Again, in C6H5NHCH3, -C6H5 group is directly attached to the N-atom. However, it is not so in C6H5CH2NH2. Thus, in C6H5NHCH3, the -R effect of -C6H5 group decreases the electron density over the N-atom. Therefore, C6H5CH2NH2 is more basic than C6H5NHCH3. Hence, the increasing order of the basic strengths of the given compounds is as follows:

C6H5NH2 < C6H5NHCH3 < C6H5CH2NH2.

(iv) In the gas phase, there is no solvation effect. As a result, the basic strength mainly depends upon the +I effect. The higher the +I effect, the stronger is the base. Also, the greater the number of alkyl groups, the higher is the +I effect. Therefore, the given compounds can be arranged in the decreasing order of their basic strengths in the gas phase as follows:

(C2H5)3N > (C2H5)2NH > C2H5NH2 > NH3

(v) The boiling points of compounds depend on the extent of H-bonding present in that compound. The more extensive the H-bonding in the compound, the higher is the boiling point. (CH3)2NH contains only one H-atom whereas C2H5NH2 contains two H-atoms. Then, C2H5NH2 undergoes more extensive H-bonding than (CH3)2NH. Hence, the boiling point of C2H5NH2 is higher than that of (CH3)2NH.

Further, O is more electronegative than N. Thus, C2H5OH forms stronger H-bonds than C2H5NH2. As a result, the boiling point of C2H5OH is higher than that of C2H5NH2 and (CH3)2NH.

Now, the given compounds can be arranged in the increasing order of their boiling points as follows:

(CH3)2NH < C2H5NH2 < C2H5OH

(vi) The more extensive the H-bonding, the higher is the solubility. C2H5NH2 contains two H-atoms whereas (C2H5)2NH contains only one H-atom. Thus, C2H5NH2 undergoes more extensive H-bonding than (C2H5)2NH. Hence, the solubility in water of C2H5NH2 is more than that of (C2H5)2NH.

Further, the solubility of amines decreases with increase in the molecular mass. This is because the molecular mass of amines increases with an increase in the size of the hydrophobic part.

The molecular mass of C6H5NH2 is greater than that of C2H5NH2 and (C2H5)2NH.

Hence, the increasing order of their solubility in water is as follows:

C6H5NH2 < (C2H5)2NH < C2H5NH2

Q.5 How will you convert:

(i) Ethanoic acid into methanamine
(ii) Hexanenitrile into 1-aminopentane
(iii) Methanol to ethanoic acid
(iv) Ethanamine into methanamine
(v) Ethanoic acid into propanoic acid
(vi) Methanamine into ethanamine
(vii) Nitromethane into dimethylamine
(viii) Propanoic acid into ethanoic acid



Q.6 Describe a method for the identification of primary, secondary and tertiary amines. Also write chemical equations of the reactions involved.


Primary, secondary and tertiary amines can be identified and distinguished by Hinsberg’s test. In this test, the amines are allowed to react with Hinsberg’s reagent, benzenesulphonyl chloride (C6H5SO2Cl). The three types of amines react differently with Hinsberg’s reagent. Therefore, they can be easily identified using Hinsberg’s reagent.

Primary amines: They react with benzenesulphonyl chloride to form N-alkylbenzenesulphonyl amide which is soluble in alkali.

Due to the presence of a strong electron-withdrawing sulphonyl group in the sulphonamide, the H-atom attached to nitrogen can be easily released as proton. So, it is acidic and dissolves in alkali.

Secondary amines: They react with Hinsberg’s reagent to give a sulphonamide which is insoluble in alkali.

There is no H-atom attached to the N-atom in the sulphonamide. Therefore, it is not acidic and insoluble in alkali.

Tertiary amines: They do not react with Hinsberg’s reagent at all.

Q.7 Write short notes on the following:
(i) Carbylamine reaction
(ii) Diazotisation
(iii) Hofmann’s bromamide reaction
(iv) Coupling reaction
(v) Ammonolysis
(vi) Acetylation
(vii) Gabriel phthalimide synthesis.


(i) Carbylamine reaction

Carbylamine reaction is used as a test for the identification of primary amines. When aliphatic and aromatic primary amines are heated with chloroform and ethanolic potassium hydroxide, carbylamines (or isocyanides) are formed. These carbylamines have very unpleasant odours. Secondary and tertiary amines do not respond to this test.

R NH 2 Primary amine Forexample, + CHCl 3 Chloroform + 3KOH( alc. ) Potassium hydroxide Δ RNC Carbylamine +3KCl+ 3H 2 O CH 3 NH 2 Methanamine + CHCl 3 +3KOH( alc. ) Δ CH 3 NC Methylcarblylamine ormethylisocyamide +3KCl+ 3H 2 O MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@117A@

(ii) Diazotisation
Aromatic primary amines react with nitrous acid (prepared in situ from NaNO2 and a mineral acid such as HCl) at low temperatures (273-278 K) to form diazonium salts. This conversion of aromatic primary amines into diazonium salts is known as diazotization. For example, on treatment with NaNO2 and HCl at 273-278 K, aniline produces benzenediazonium chloride, with NaCl and H2O as by-products.

(iii) Hoffmann bromamide reaction

When an amide is treated with bromine in an aqueous or ethanolic Solution of sodium hydroxide, a primary amine with one carbon atom less than the original amide is produced. This degradation reaction is known as Hoffmann bromamide reaction. This reaction involves the migration of an alkyl or aryl group from the carbonyl carbon atom of the amide to the nitrogen atom.

(iv) Coupling reaction

The reaction of joining two aromatic rings through the -N=N-bond is known as coupling reaction. Arenediazonium salts such as benzene diazonium salts react with phenol or aromatic amines to form coloured azo compounds.

It can be observed that, the para-positions of phenol and aniline are coupled with the diazonium salt. This reaction proceeds through electrophilic substitution.

(v) Ammonolysis

When an alkyl or benzyl halide is allowed to react with an ethanolic Solution of ammonia, it undergoes nucleophilic substitution reaction in which the halogen atom is replaced by an amino (-NH2) group. This process of cleavage of the carbon-halogen bond is known as ammonolysis.

When this substituted ammonium salt is treated with a strong base such as sodium hydroxide, amine is obtained.

R N + H 3 X +NaOH R NH 2 Amine + H 2 O+NaX MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqk0xg9LrFfpeea0xh9v8qiW7rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeaacaGaaiaabeqaamaabaabaaGcbaGaaeOuaiaaykW7caqGtaIaaGPaVpaaxacabaGaaeOtaaWcbeqaaiabgUcaRaaakiaabIeadaWgaaWcbaGaae4maaqabaGccaaMc8+aaCbiaeaacaqGybaaleqabaGaeyOeI0caaOGaaGPaVlaabUcacaaMc8UaaeOtaiaabggacaqGpbGaaeisaiaaykW7daGdKaWcbaaabeGccaGLsgcacaaMc8+aaCbeaeaacaqGsbGaaGPaVlaabobicaaMc8UaaeOtaiaabIeadaWgaaWcbaGaaeOmaaqabaaabaGaaeyqaiaab2gacaqGPbGaaeOBaiaabwgaaeqaaOGaaGPaVlaabUcacaaMc8UaaeisamaaBaaaleaacaqGYaaabeaakiaab+eacaaMc8Uaae4kaiaaykW7caqGobGaaeyyaiaabIfaaaa@6868@

Though primary amine is produced as the major product, this process produces a mixture of primary, secondary and tertiary amines, and also a quaternary ammonium salt as shown.

RNH 2 ( ) RX R 2 NH ( ) RX R 3 N ( ) RX R 4 N + X Quaternary ammoniumsalt MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVy0xg9vqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@79C0@

(vi) Acetylation

Acetylation (or ethanoylation) is the process of introducing an acetyl group into a molecule.

Aliphatic and aromatic primary and secondary amines undergo acetylation reaction by nucleophilic substitution when treated with acid chlorides, anhydrides or esters. This reaction involves the replacement of the hydrogen atom of -NH2 or > NH group by the acetyl group, which in turn leads to the production of amides. To shift the equilibrium to the right hand side, the HCl formed during the reaction is removed as soon as it is formed. This reaction is carried out in the presence of a base (such as pyridine) which is stronger than the amine.

When amines react with benzoyl chloride., the reaction is also known as benzoylation. For example,

(vii) Gabriel phthalimide synthesis

Gabriel phthalimide synthesis is a very useful method for the preparation of aliphatic primary amines. It involves the treatment of phthalimide with ethanolic potassium hydroxide to form potassium salt of phthalimide. This salt is further heated with alkyl halide, followed by alkaline hydrolysis to yield the corresponding primary amine.

Q.8 Accomplish the following conversions:

(i) Nitrobenzene to benzoic acid
(ii) Benzene to m-bromophenol
(iii) Benzoic acid to aniline
(iv) Aniline to 2,4,6-tribromofluorobenzene
(v) Benzyl chloride to 2-phenylethanamine
(vi) Chlorobenzene to p-chloroaniline
(vii) Aniline to p-bromoaniline
(viii) Benzamide to toluene
(ix) Aniline to benzyl alcohol.


Q.9 Give the structures of A, B and C in the following reactions:



Q.10 An aromatic compound ‘A’ on treatment with aqueous ammonia and heating forms compound ‘B’ which on heating with Br2 and KOH forms a compound ‘C’ of molecular formula C6H7N. Write the structures and IUPAC names of compounds A, B and C.


It is given that compound ‘C’ having the molecular formula, C6H7N is formed by heating compound ‘B’ with Br2 and KOH. This is a Hoffmann bromamide degradation reaction. Therefore, compound ‘B’ is an amide and compound ‘C’ is an amine. The only amine having the molecular formula, C6H7N is aniline, (C6H5NH2).

Therefore, compound ‘B’ (from which ‘C’ is formed) must be benzamide, (C6H5CONH2).

Further, benzamide is formed by heating compound ‘A’ with aqueous ammonia. Therefore, compound ‘A’ must be benzoic acid.

The given reactions can be explained with the help of the following equations:

Q.11 Complete the following reactions:

(i) C6H5NH2 + CHCl3 + alc.KOH →
(ii) C6H5N2Cl + H3PO2+ H2O →
(iii) C6H5NH2 + H2SO4(conc.) →
(iv) C6H5N2Cl + C2H5OH →
(v) C6H5NH2 + Br2(aq) →
(vi) C6H5NH2 + (CH3CO)2O →

( vii ) C 6 H 5 N 2 Cl (ii) NaNO 2 /CuΔ (i) HBF 4 MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVy0xg9vqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeaacaGaaiaabeqaamaabaabaaGcbiqaaaQddaqadaqaaiaabAhacaqGPbGaaeyAaaGaayjkaiaawMcaaiaaykW7caqGdbWaaSbaaSqaaiaabAdaaeqaaOGaaeisamaaBaaaleaacaqG1aaabeaakiaab6eadaWgaaWcbaGaaeOmaaqabaGccaqGdbGaaeiBaiaaykW7daGdSaWcbaGaaeikaiaabMgacaqGPaGaaGPaVlaabIeacaqGcbGaaeOramaaBaaameaacaqG0aaabeaaaSqaaiaabIcacaqGPbGaaeyAaiaabMcacaaMc8UaaeOtaiaabggacaqGobGaae4tamaaBaaameaacaqGYaaabeaaliaab+cacaqGdbGaaeyDaiaabs5aaOGaayPKHaaaaa@5A2F@


( i ) C 6 H 5 NH 2 Aniline + CHCl 3 +3alc.KOH Carbylamine reaction 3H 2 O+3KCl+ C 6 H 5 NC Phenyl isocyanide ( ii ) C 6 H 5 N 2 Cl Benzenediazonium chloride + H 3 PO 2 + H 2 O C 6 H 6 Benzene + N 2 + H 3 PO 3 +HCl ( iii ) C 6 H 5 NH 2 Aniline +conc .H 2 SO 4 C 6 H 5 N + H 3 HS O 4 Aniliniumhydrogensulphate ( iv ) C 6 H 5 N 2 Cl Benzenediazonium chloride + C 2 H 5 OH Ethanol C 6 H 6 Benzene + CH 3 CHO Ethanal + N 2 +HCl MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVy0xg9vqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=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@8B9B@


Q.12 Why cannot aromatic primary amines be prepared by Gabriel phthalimide synthesis?


Gabriel phthalimide synthesis is used for the preparation of aliphatic primary amines. It involves nucleophilic substitution (SN2) of alkyl halides by the anion formed by the phthalimide.

But aryl halides do not undergo nucleophilic substitution with the anion formed by the phthalimide.

Hence, aromatic primary amines cannot be prepared by this process.

Q.13 Write the reactions of (i) aromatic and (ii) aliphatic primary amines with nitrous acid.


(i) Aromatic amines react with nitrous acid (prepared in situ from NaNO2 and a mineral acid such as HCl) at 273 – 278K to form stable aromatic diazonium salts, NaCl and H2O.

(ii) Aliphatic primary amines react with nitrous acid (prepared in situ from NaNO2 and a mineral acid such as HCl) to form unstable aliphatic diazonium salts, which further produce alcohol and HCl with the evolution of N2 gas.

Q.14 Give plausible explanation for each of the following:

(i) Why are amines less acidic than alcohols of comparable molecular masses?
(ii) Why do primary amines have higher boiling point than tertiary amines?
(iii) Why are aliphatic amines stronger bases than aromatic amines?


(i) Amines undergo protonation to give amide ion.

R NH 2 R N H Amideion + H + MathType@MTEF@5@5@+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbGeaGqiVy0xg9vqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeaacaGaaiaabeqaamaabaabaaGceiqabeaaG6qaaiaabkfacaaMc8Uaae4eGiaaykW7caqGobGaaeisamaaBaaaleaacaqGYaaabeaakiaaykW7daGdKaWcbaaabeGccaGLsgcacaaMc8+aaCbeaeaacaqGsbGaaGPaVlaabobicaaMc8+aaCbiaeaacaqGobaaleqabaGaaeylaaaakiaabIeaaSqaaiaabgeacaqGTbGaaeyAaiaabsgacaqGLbGaaGPaVlaabMgacaqGVbGaaeOBaaqabaGccaaMc8Uaae4kaiaaykW7caqGibWaaWbaaSqabeaacaqGRaaaaaGcbaaaaaa@583F@

Similarly, alcohol loses a proton to give alkoxide ion.

R-OH → R-O + H+

Alkoxide ion

In an amide ion, the negative charge is on the N-atom whereas in alkoxide ion, the negative charge is on the O-atom. Since O is more electronegative than N, O can accommodate the negative charge more easily than N. As a result, the amide ion is less stable than the alkoxide ion. Hence, amines are less acidic than alcohols of comparable molecular masses.

(ii) In a molecule of tertiary amine, there are no H-atoms whereas in primary amines, two hydrogen atoms are present. Due to the presence of H-atoms, primary amines undergo extensive intermolecular H-bonding.

As a result, extra energy is required to separate the molecules of primary amines. Hence, primary amines have higher boiling points than tertiary amines.

(iii) Due to the -R effect of the benzene ring, the electrons on the N- atom are less available in case of aromatic amines. Therefore, the electrons on the N-atom in aromatic amines cannot be donated easily. This explains why aliphatic amines are stronger bases than aromatic amines.

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FAQs (Frequently Asked Questions)

1. What are the Three Amine Categories?

An amine is Classified as primary, secondary, or tertiary based on the number of hydrogen atoms replaced by ammonia by organic groups. A primary amine is generated when a single hydrogen atom is replaced.

Secondary and tertiary Amines are generated when two or three hydrogen atoms are replaced. Multiple questions on this Classification will be asked of students appearing for Boards. As a result, students should have a firm grasp of the subject.

Students may also use NCERT Solutions For Class 12 Chemistry Chapter 13. Visit the links to gain a thorough understanding of the subject.

2. Why should I use NCERT Solutions Class 12 Chemistry Amines?

Amine is a subject that necessitates conceptual clarity. To do well in the examination, students must understand each subtopic thoroughly. It may, however, be impossible to do so without competent instructions and guidance. In this situation, students can use the links to obtain NCERT Solutions For Class 12 Chemistry Chapter 13. They have easy access to these solutions from any location. All of the questions are explained thoroughly. For easier understanding, multiple illustrations are provided, and the language used in these solutions is simple.


Furthermore, it will enable students to study a topic at their leisure. These solutions are available for free unlimited access. Students can use the Solutions to double-check their answers once they complete the book exercises independently.

3. How should I prepare for my board examinations for amines?

‘Amines’ is an essential topic to study for Board Examinations and other competitive Examinations. Furthermore, students should concentrate on the amine categories while studying for this. They should also get themselves familiar with all the IUPAC names. They must be familiar with the chemical characteristics of Amines. On the other hand, exploring all of these areas without good direction may be challenging. 

4. How can students benefit from the NCERT Solutions Class 12 Chemistry Chapter 13 created by Extramarks?

The concept of amines necessitates student mental clarity. To perform well on the second-term tests, students should understand the concepts covered in each Chapter. Students can choose an excellent study material that meets their needs while answering the specified official textbook questions. Extramarks provide access links to solutions, which students can use to answer their questions quickly and easily.