Ncert Solutions Chemistry Class 12th

Chapter 10 Biomolecules of Class 12 Chemistry includes several important topics which are frequently asked in the state and cbses board exams. The most important topics in the Biomolecules chapter include the classification and structure of carbohydrates (monosaccharides, disaccharides, polysaccharides), amino acids and proteins (including peptide bond formation), enzymes and their characteristics, nucleic acids (DNA and RNA structure and components), and vitamins with their types and deficiencies.

Questions often focus on structural identification, naming, and functions of biomolecules, as well as simple reactions like hydrolysis and oxidation. Students should also pay attention to zwitterion structure in amino acids, enzyme action mechanisms, and differences between DNA and RNA. Students must practice diagrams and learn key functions of each biomolecule to score full marks in this chapter. Students can take help of NCERT Solutioins for Class 12 Chemistry Biomolecules to get good understanding of the concepts and requirements.

Biomolecules are organic compounds essential to life, found in all living organisms. Biomolecules include carbohydrates, proteins, lipids, nucleic acids, enzymes, and vitamins.

NCERT Class 12 Chemistry chapter 10 Biomolecules covers the molecular basis of life, including the structure, types, and functions of each biomolecule. This chapter is important because it connects chemistry to biology and helps students understand metabolism, heredity, and biochemical reactions. It also forms the foundation for higher studies in medicine, biochemistry, and biotechnology. Biomolecules are also frequently tested in CBSE board exams and competitive exams like NEET and JEE, making it a crucial topic to master.

Diazonium salts are formed by treating primary aromatic amines (such as aniline) with nitrous acid (generated in situ from NaNO? and HCl) at low temperatures (0–5°C). A common example is benzene diazonium chloride (C? H? N? Cl? ). Diazonium salts contain the functional group –N? X? , where X? is typically a halide like Cl? or Br?

These salts are important because they are highly reactive intermediates used in various chemical processes, Check below;

• Azo dye synthesis (via coupling reactions)

• Replacement reactions to introduce functional groups like –OH, –CN, –X (halides)

• Various organic conversions in synthetic chemistry (vital role in dye, drug, and polymer industries)

Amines are prepared by replacing the hydrogen atom with alkyl or aryl groups from amonia (NH? ). Students can differntiate Aliphatic and aromatic amines differ based on the type of group attached to the nitrogen atom. 

• Aliphatic amines have one or more alkyl groups (like methyl or ethyl) bonded to the nitrogen, such as ethylamine (CH? NH? ). 
• Aromatic amines have an aryl group (like benzene) directly bonded to nitrogen, for example, aniline (C? H? NH? ).

Aliphatic amines are generally more basic than aromatic amines because, in aromatic amines, the lone pair on nitrogen is delocalized into the aromatic ring through resonance, reducing its availability for protonation. This structural difference affects their chemical reactivity, basicity, and physical properties.

Students can check Class 12 Chemistry Chapter 9 Amines NCERT Solutions, which can help you know name chemical reactions crucial for CBSE Board Exams and Competitive Exams like JEE and NEET:

• Gabriel Phthalimide Synthesis – Used to prepare primary amines from phthalimide via hydrolysis.

• Hoffmann Bromamide Degradation Reaction – Converts amides to primary amines with one less carbon atom using Br? and NaOH.

• Carbylamine Reaction – A test for primary amines where they react with chloroform and KOH to form isocyanides (foul-smelling).

• Acylation and Alkylation of Amines – Involves the reaction of amines with acid chlorides or alkyl halides.

• Coupling Reaction – Aryldiazonium salts react with phenols or aromatic amines to form azo dyes.

Amines are organic compounds derived from ammonia (NH3 ) by replacing hydrogen atoms with alkyl or aryl groups. They are classified as primary, secondary, or tertiary based on the number of hydrogen substitutions. Their nomenclature follows IUPAC rules, using the suffix “-amine.” There are several important topics discussed throghout the chapter 9 amines such as Preparation methods, physical properties, chemical properties and named reactions.

Amines are synthesized through methods like reduction of nitro compounds, ammonolysis, Gabriel phthalimide synthesis, and Hoffmann bromamide degradation.  In terms of physical properties, Amines exhibit hydrogen bonding, affecting their boiling points and solubility. Chemically, amines are basic in nature and undergo alkylation, acylation, and electrophilic substitution in aromatic amines. Amines are widely used in chemical industries; pharmaceuticals, dyes, and organic synthesis e.g. diazonium salts, formed from aromatic amines, are crucial in dye synthesis. Students can check NCERT Solutions of Class 12 Chemistry Amines for better preparation for boards and other competiive exam.