12 Questions
What type of isomerism is exhibited by different types of amines?
Structural isomerism
How many isomeric amines are possible for the molecular formula C4H11N?
Eight
Which of the following compounds can act as a Lewis base?
C6H6
How can you convert Cl-(CH2)4-Cl into Hexane-1,6-diamine?
By nucleophilic substitution
Which compound among the following amines has the highest basic strength?
(C2H5)3N
What hybridization does the nitrogen atom in amines exhibit?
sp3
Why is the pKb value of aniline more than that of methylamine?
Aniline has a delocalized lone pair of electrons over the benzene ring, reducing electron density on the nitrogen atom.
Why does aniline not undergo Friedel-Crafts reaction?
The lone pair on the nitrogen atom in aniline hinders the electrophilic attack by Lewis acids in Friedel-Crafts reactions.
Why does aniline give a substantial amount of m-nitroaniline upon nitration?
The amino group directs the incoming nitro group to the meta position.
What makes diazonium salts of aromatic amines more stable compared to those of aliphatic amines?
The aromatic ring resonance in diazonium salts stabilizes them.
Why is Gabriel phthalimide synthesis preferred for synthesizing primary amines?
It specifically targets primary amines without forming by-products.
Why does aniline not dissolve in water while ethylamine does?
Ethylamine's alkyl chain increases its polarity and solubility in water.
Study Notes
Class 12 Chemistry Chapter 13 Amines
Classification of Amines
- Primary amines: (i) CH₃NH₂, (ii) C₆H₅NH₂
- Secondary amines: (iii) (C₂H₅)₂NH
- Tertiary amines: (iv) (C₂H₅)₃N
Isomeric Amines
- Eight isomeric amines are possible with the molecular formula C₄H₁₁N
- Types of isomerism exhibited by different amines: structural isomerism
Conversion of Compounds
- Benzene into aniline: nitration of benzene followed by reduction
- Benzene into N,N-dimethylaniline: methylation of aniline
- Cl-(CH₂)₄-Cl into Hexane-1,6-diamine: reduction of the haloalkane
Basic Strength of Amines
- Basic character of amines linked to availability of lone electron pair on the nitrogen atom
- Factors affecting basic strength: +I effect, steric hindrance, and delocalization
- pKb value: related to Kb as pKb = -log Kb
Acid-Base Reactions
- CH₃CH₂CH₂NH₂ + HCl →
- (C₂H₅)₃N + HCl →
Alkylation of Aniline
- Reaction of aniline with excess of methyl iodide in the presence of sodium carbonate solution
Reaction of Aniline with Benzoyl Chloride
- Formation of an amide
Isomers of C₃H₉N
- Four structural isomers are possible
- IUPAC names of the isomers:
- 1° amine: CH₃CH₂NH₂
- 1° amine: (CH₃)₂CHNH₂
- 2° amine: CH₃NHCH(CH₃)₂
- 3° amine: (CH₃)₃CNH₂
Test your knowledge on the topics and subtopics covered in NCERT Solutions for Class 12 Chemistry Chapter 13 Amines. Questions include classification of amines as primary, secondary, or tertiary, and writing structures of isomeric amines. Practice and enhance your understanding of amines with this quiz.
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