Fundamental Of Chemistry (रसायन विज्ञान के आधारभूत सिद्धांत)

Units

Topics

1

a)       Chemical techniques in ancient India – General Introduction.

b)       Contribution of ancient Indian scientists in chemistry, e.g., metallurgy, dyes, pigments, cosmetics, Ayurveda, Charak Sanhita.

Atomic Structure:

i)         Review of Bohr’s theory and its limitations. Atomic spectrum of Hydrogen. Dual nature of particles and waves, de Broglie’s equation, Heisenberg’s Uncertainty principle and its significance. Uncertainty principle and its significance.

ii)       Quantum numbers and their significance. Rules for filling electrons in various orbitals, Pauli’s Exclusion Principle, Hund’s rule of maximum multiplicity, Aufbau principle and its limitations, Variation of orbital energy with atomic number.Electronic configurations of the atoms. Stability of half-filled and completely filled orbitals, concept of exchange energy. Relative energies of atomic orbitals, Anomalous electronic configurations.

2

Elementary idea of the following properties of the elements with reference to s & p-block elements in periodic table.

·         Effective nuclear number (EAN), shielding or screening effect, Slater rules, variation of effective nuclear charge in periodic table.

·         Atomic radii (van der Waals).

·         Ionic and crystal radii.

·         Covalent radii (octahedral and tetrahedral).

Detailed discussion of the following properties of the elements, with reference to s & p-blocks.

·         Ionisation   energy – Successive   ionisation   energy   and   factors affecting ionisation energy. Applications of ionisation energy.

·         Electronegativity– Pauling’s/ Mulliken’s electronegativity scales. Variation of electronegativity with bond order, partial charge, hybridisation.

3

Chemical Bonding

i)         Ionic Bonding: General characteristics of ionic bonding.

Ionic Bonding and Energy: Lattice and solvation energies and their importance in the context of stability and solubility of ionic compounds. Statement of Born-Lande equation for calculation of lattice energy, Madelung constant, Born-Haber cycle and its applications. Covalent character in ionic compounds, polarising power and polarisability, Fajan’s rules.

ii)       Covalent Bonding: Lewis structure, Valence Bond theory (Heitler- London approach).

Hybridisation – Concept, types (sp, sp², sp³, dsp², d²sp³) with suitable examples of inorganic and organic molecules.

Ionic character in covalent compounds–dipole moment and percentage ionic character.

        Valence Shell Electron Pair Repulsion Theory (VSEPR) theory– Assumptions, need of theory, application of theory to explain geometries or shapes of some inorganic molecules and ions on the basis of VSEPR and hybridisation with suitable examples of linear, trigonal planar, square planar, tetrahedral, trigonal bipyramidal and octahedral arrangements such as–NH₃, H₂O, SF₄, ClF₃, PCl₅, SF₆, ClF₅, XeF₄.

Molecular Orbital (MO) Concept of Bonding

The approximations of the theory, Linear combination of atomic orbitals (LCAO) (elementary pictorial approach).

Rules for the LCAO method, bonding and antibonding MOs. Characteristics for s-s, s-p and p-p combinations of atomic orbitals, non-bonding combination of orbitals. MO diagrams of homonuclear diatomic molecules– H₂, Li₂, Be₂,. B₂, C₂, N₂, O₂, F₂, and their ions. Molecular orbitals of heteronuclear diatomic molecules– CO, NO, CN, HF.

Bond Parameters: Definition and factors affecting – bond orders, bond lengths, bond angles.

4

Acid-Base Concept

Arrhenius concept, Bronsted-Lowry’s concept, conjugate acids and bases, relative strength of acids, Lewis concept, pH, buffer solutions. Acid-base neutralisation curves, Handerson equation.

Strength of Organic Acids and Bases: Comparative study with emphasis on factors affecting pK values.

Indicator, choice of indicators.

5

a)       Fundamentals of Organic Chemistry

Structure, shape and reactivity of organic molecules:

Physical Effects, Electronic Displacements: Inductive Effect, Electromeric Effect, Resonance and Hyperconjugation.

Cleavage of Bonds: Homolysis and Heterolysis.

Reactive Intermediates: Carbocations, Carbanions and free radicals. Nucleophiles and electrophiles.

b)       Stereochemistry of Organic Compounds:

Concept of isomerism.

Geometrical Isomerism: Determination of configuration of geometric isomers. E&Z system of nomenclature, geometric isomerism in oximes and alicyclic compounds.

Optical Isomerism: Elements of symmetry, molecular chirality, enantiomers and their properties, stereogenic centre, optical activity of enantiomers.

Concept of Chirality (up to two Carbon Atoms): Chiral and achiral molecules with two stereogeniccentres, diastereomers, threo and erythroisomers, meso isomer, resolution of enantiomers, inversion, retention and racemisation. Relative and absolute configuration, sequence rules, D&L and R&S systems of nomenclature.

Conformations and Conformational Analysis

Conformations of ethane, butane and cyclohexane. Interconversion of Wedge Formula, Newman, Sawhorse and Fischer representations.

6

Chemical Kinetics: Rate of reaction, Definition and difference of order and molecularity. Derivation of rate constants for first, second, third and zero order reactions and examples. Derivation for half-life period. Methods to determine the order of reactions. Effect of temperature on rate of reaction, Arrhenius equation, concept of activation energy.

Ionic Equilibria: Strong, moderate and weak electrolytes, degree of ionisation, factors affecting degree of ionisation, ionisation constant and ionic product of water. Common ion effect.

Salt hydrolysis–calculation of hydrolysis constant, degree of hydrolysis and pH for different salts. Solubility and solubility product of sparingly soluble salts – applications of solubility product.