NCERT Solutions for Class 12 Chemistry Chapter 9 Amines – Free PDF Download

Here is a quick summary of the NCERT Amines solutions:

• Amines are the derivatives of ammonia. They are obtained from the replacement of hydrogen atoms with alkyl or aryl groups.
• The amines can be classified as primary, secondary, and tertiary amines.
• If the alkyl or aryl groups are the same, the secondary and tertiary amines are known as simple amines, and if the groups are different, it is called mixed amines.
• Amines are normally composed of halides, nitro compounds, imides, amides, etc.
• Other concepts covered in this chapter include alkylamines, aromatic amines, aniline,  acylation, aryldiazonium salts, and trimethylamine.

To get the NCERT Class 12 notes of all three subjects, including Physics, Chemistry, and Maths, check here. It offers in-depth conceptual knowledge in an easy and simple language.

In NCERT Solutions Amines, students must focus on the classification, nomenclature, preparation, structure, chemical and physical properties of amines. It is important to understand the basic character of amines and their reactions. The key topics to focus on are the primary, secondary, and tertiary amines and diazonium salts. Here are the topics covered in this chapter:

Exercise	Topics Covered
9.1	Structure of Amines
9.2	Classification
9.3	Nomenclature
9.4	Preparation of Amines
9.5	Physical Properties
9.6	Chemical Reactions
9.7	Method of Preparation of Diazoniun Salts
9.8	Physical Properties
9.9	Chemical Reactions
9.10	Importance of Diazonium Salts in Synthesis of Aromatic Compounds

Class 12 Chemistry Chapter 9 Amines Weightage in NEET, JEE Mains

Exam	Number of Questions	Weightage
NEET	-	3.80%
JEE Mains	9-10 questions	3.8%

Key Topics covered in Class 12 Chemistry Chapter 9 Amines

1. Structure of Amines
2. Classification
3. Nomenclature
4. Preparation of Amines
5. Physical Properties
6. Chemical Reactions
7. Methods of preparation of Diazonium Salts
8. Physical Properties
9. Chemical reactions
10. Importance of Diazonium salts in Synthesis of aromatic Compounds

Important Reactions of NCERT Class 12 Chemistry: Amines for CBSE and other Competitive Exams

1. Preparation of Amines  

• Reduction of Nitro Compounds  
  RNO₂ + H₂ → RNH₂ (Sn/HCl or Fe/HCl)  
• Ammonolysis of Alkyl Halides  
  RX + NH₃ → RNH₂ + HX  
• Gabriel Phthalimide Synthesis (For Primary Amines Only)  
  C₆H₄(CO)₂N⁻K⁺ + RX → C₆H₄(CO)₂NR  
  C₆H₄(CO)₂NR + H₂O → RNH₂  
• Hoffmann Bromamide Reaction  
  RCONH₂ + Br₂ + NaOH → RNH₂ + Na₂CO₃ + NaBr + H₂O  

2. Chemical Reactions of Amines  

• Basic Nature of Amines  
  RNH₂ + H₂O → RNH₃⁺ + OH⁻  
• Reaction with Acids (Salt Formation)  
  RNH₂ + HCl → RNH₃⁺Cl⁻  
• Alkylation (Formation of Higher Amines)  
  RNH₂ + R'X → RNHR'  
• Acylation (Reaction with Acid Chlorides & Anhydrides)  
  RNH₂ + R'COCl → RNHCOR'  
• Reaction with Nitrous Acid (Different Products Based on Amine Type)  
  Primary Amine: RNH₂ + HNO₂ → ROH + N₂ + H₂O  
  Secondary Amine: R₂NH + HNO₂ → R₂NN=O (Nitrosoamine)   
• Hinsberg Test (Distinguishing Primary, Secondary & Tertiary Amines)  
  Primary Amines → Forms soluble sulfonamide  
  Secondary Amines → Forms insoluble sulfonamide  
• Carbylamine Reaction (For Primary Amines Only, Test for Primary Amines)  
  RNH₂ + CHCl₃ + KOH → RNC (Foulsmelling isocyanide)  
• Electrophilic Substitution in Aromatic Amines  
  
  • Bromination:  C₆H₅NH₂ + Br₂ → 2,4,6Tribromoaniline  
  • Nitration:  C₆H₅NH₂ + HNO₃ → mNitroaniline  
  • Sulphonation: C₆H₅NH₂ + H₂SO₄ → pAminobenzenesulphonic Acid  
• Diazotization Reaction (Formation of Diazonium Salts from Primary Aromatic Amines)  
  C₆H₅NH₂ + HNO₂ → C₆H₅N₂⁺Cl⁻ + H₂O  
• Coupling Reactions (Reaction of Diazonium Salts with Phenols & Amines)  
  C₆H₅N₂⁺Cl⁻ + C₆H₅OH → pHydroxyazobenzene  
  C₆H₅N₂⁺Cl⁻ + C₆H₅NH₂ → pAminoazobenzene  

The Class 12 Science students must download the free NCERT Amines PDF from the link given below. The solutions are created by the subject matter experts. It will help the students to improve their exam preparation.

Class 12 Chemistry Chapter 9 Amines NCERT Solutions PDF Download: Download Free PDF 

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Q 13.1 Classify the following amines as primary, secondary or tertiary.

Ans (i) Primary, because the nitrogen atom is attached to the only 1 carbon atom. (ii) Tertiary, because the Nitrogen atom is attached to the 3 carbon atoms. (iii) Primary, because the nitrogen atom is attached to the only 1 carbon atom. (iv) Secondary, because the nitrogen atom is attached to the only 1 carbon.

Q 13.2 (i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N. (ii) Write IUPAC names of all the isomers. (iii) What type of isomerism is exhibited by different pairs of amines?

Ans (i) & (ii) There are total 8 geometrical isomers of the given compound. (iii) a) Pairs 1,2,6,7 Exhibit Position isomerism; means the change in position of the substituent. b) Pairs 1,3 and 1,4 and 2,3 and 2,4 exhibit chain isomerism i.e. in this type of isomerism the different structures can be produced by changing the chain of the c) Pairs 5,6 and 5,7 exhibit metamerism; e. different group on either side of the central atom. d) All Primary amines exhibit functional isomers. All secondary amines share functional isomerism and same for The functional isomerism means same functional group.

Q 13.3 How will you convert (i) Benzene into aniline (ii) Benzene into N, N-dimethylaniline (iii) Cl–(CH2)4–Cl into hexan-1,6-diamine?

Ans Benzene into aniline When Benzene is treated with HNO3/H2SO4 it forms nitrobenzene. When Nitrobenzene reduced with Sn/HCL it forms Aniline because Sn/HCl is a reducing Mixture. When Benzene is reacted with nitrating mixture it forms nitrobenzene. When it Reduced H2/Pd in ethanol or Sn/HCl, it forms Aniline. When Aniline reacts 2 times with CH3Cl It forms N, N- dimethylaniline. When 1,4-dichlorobutane reacts with NaCN it forms Di cyanide compound, After Hydrogenation it forms the Hexane 1,6-Diamine.

Q 13.4 Arrange the following in increasing order of their basic strength:  (i) C2H5NH2, C6H5NH2, NH3, C6H5CH2NH2 and (C2H5)2NH (ii) C2H5NH2, (C2H5 )2NH, (C2H5 )3N, C6H5NH2 (iii) CH3NH2, (CH3 )2NH, (CH3)3N, C6H5NH2, C6H5CH2 NH2 .

Ans 1- Alkyl group contribute inductive effect which increases the basic strength of NH3 2H5NH2<(C2H5)2NH. Then C6H5NH2 is having –I effect that reduces strength. And C6H5CH2NH2 increases the basic strength but not as much as C2H5 group. Hence final order will be C6H5NH2< 3 6H 5CH 2NH 2 2H 5NH 2<(C 2H 5) 2NH.  2- By taking into consideration –R effect and steric hindrance of groups we can arrange them in the order C6H5NH2< C2H5NH2<(C2H5)3N<(C2H5)2NH. Because (C2H5)3N has a lot of steric hindrances that reduces the basic strength. 3- In C6H5NH2 , N is directly attached to the ring that causes delocalization of electrons of the benzene ring. Whereas in case of C6H5CH2NH2 it is not directly connected to benzene ring Hence it has more basic strength. Due to –I effect of (CH3)3 – a group it has more basic strength than C6H5CH2NH2. Hence final order will be C6H5NH2< C6H5CH2NH2<(CH3)3N< CH3NH2< (CH3)2NH

Students who are in class 12 can benefit from NCERT solutions for class 12 chapter 9 in the following ways. 

• Conceptual Knowledge: Students' basic concepts become clear by attempting various questions that help solve the problem easily. 

• Improve problem-solving skills: The complex solutions provided are explained in a simple way, which helps students easily solve the questions. 

• Revision and Practice: Students while preparing for the examination, can use the Amines ncert solutions for self-assessment. Knowing the weaker topics, students can focus on it.