Optional
Chemistry
UPSC Civil Services Mains, optional subject
Syllabus
Paper I
- Atomic Structure
- Heisenberg's uncertainty principle Schrodinger wave equation (time independent)
- Interpretation of wave function, particle in one- dimensional box, quantum numbers, hydrogen atom wave functions
- Shapes of s, p and d orbitals.
- Chemical bonding
- Ionic bond, characteristics of ionic compounds, lattice energy, Born-Haber cycle
- covalent bond and its general characteristics, polarities of bonds in molecules and their dipole moments
- Valence bond theory, concept of resonance and resonance energy
- Molecular orbital theory (LCAO method)
- bonding H₂⁺, H₂ He₂⁺ to Ne₂, NO, CO, HF, CN⁻, Comparison of valence bond and molecular orbital theories, bond order, bond strength and bond length.
- Solid state
- Crystal systems
- Designation of crystal faces, lattice structures and unit cell
- Bragg's law
- X-ray diffraction by crystals
- Close packing, radius ratio rules, calculation of some limiting radius ratio values
- Structures of NaCl, ZnS, CsCl, CaF₂
- stoichiometric and nonstoichiometric defects, impurity defects, semi-conductors.
- The gaseous state and Transport Phenomenon
- Equation of state for real gases, intermolecular interactions, and critical phenomena and liquefaction of gases
- Maxwell’s distribution of speeds, intermolecular collisions, collisions on the wall and effusion
- Thermal conductivity and viscosity of ideal gases.
- Liquid State
- Kelvin equation
- Surface tension and surface energy, wetting and contact angle, interfacial tension and capillary action.
- Thermodynamics
- Work, heat and internal energy
- first law of thermodynamics.
- Second law of thermodynamics
- entropy as a state function, entropy changes in various processes, entropy-reversibility and irreversibility, Free energy functions
- Thermodynamic equation of state
- Maxwell relations
- Temperature, volume and pressure dependence of U, H, A, G, Cp and Cv, α and β
- J-T effect and inversion temperature
- criteria for equilibrium, relation between equilibrium constant and thermodynamic quantities
- Nernst heat theorem, introductory idea of third law of thermodynamics.
- Phase equilibria and solutions
- Clausius-Clapeyron equation
- phase diagram for a pure substance
- phase equilibria in binary systems, partially miscible liquids—upper and lower critical solution temperatures
- partial molar quantities, their significance and determination
- excess thermodynamic functions and their determination.
- Electrochemistry
- Debye-Huckel theory of strong electrolytes and Debye-Huckel limiting Law for various equilibrium and transport properties.
- Galvanic cells, concentration cells
- electrochemical series, measurement of e.m.f. of cells and its applications fuel cells and batteries.
- Processes at electrodes
- double layer at the interface
- rate of charge transfer, current density
- overpotential
- electroanalytical techniques : amperometry, ion selective electrodes and their use.
- Chemical kinetics
- Differential and integral rate equations for zeroth, first, second and fractional order reactions
- Rate equations involving reverse, parallel, consecutive and chain reactions
- Branching chain and explosions
- effect of temperature and pressure on rate constant.
- Study of fast reactions by stop-flow and relaxation methods.
- Collisions and transition state theories.
- Photochemistry
- Absorption of light
- decay of excited state by different routes
- photochemical reactions between hydrogen and halogens and their quantum yields.
- Surface phenomena and catalysis
- Adsorption from gases and solutions on solid adsorbents
- Langmuir and B.E.T. adsorption isotherms
- determination of surface area, characteristics and mechanism of reaction on heterogeneous catalysts.
- Bio-inorganic chemistryMetal ions in biological systems and their role in ion-transport across the membranes (molecular mechanism), oxygen-uptake proteins, cytochromes and ferrodoxins.
- Coordination chemistry
- (i) Bonding in transition of metal complexes.
- Valence bond theory, crystal field theory and its modifications
- applications of theories in the explanation of magnetism and electronic spectra of metal complexes.
- (ii) Isomerism in coordination compounds
- IUPAC nomenclature of coordination compounds
- stereochemistry of complexes with 4 and 6 coordination numbers
- chelate effect and polynuclear complexes
- trans effect and its theories
- kinetics of substitution reactions in square-planar complexes
- thermodynamic and kinetic stability of complexes.
- (iii) EAN rule, Synthesis structure and reactivity of metal carbonyls
- carboxylate anions, carbonyl hydrides and metal nitrosyl compounds.
- (iv) Complexes with aromatic systems, synthesis, structure and bonding in metal olefin complexes, alkyne complexes and cyclopentadienyl complexes
- coordinative unsaturation, oxidative addition reactions, insertion reactions, fluxional molecules and their characterization
- Compounds with metal—metal bonds and metal atom clusters.
- Main Group Chemistry
- Boranes, borazines, phosphazenes and cyclic phosphazene, silicates and silicones, Interhalogen compounds
- Sulphur—nitrogen compounds, noble gas compounds.
- General Chemistry of ‘f’ Block Element
- Lanthanides and actinides: separation, oxidation states, magnetic and spectral properties
- lanthanide contraction.
Paper II
- Delocalised covalent bonding
- Aromaticity, anti-aromaticity
- annulenes, azulenes, tropolones, fulvenes, sydnones.
- Reaction mechanisms
- General methods (both kinetic and non-kinetic) of study of mechanisms or organic reactions : isotopies, method cross-over experiment, intermediate trapping, stereochemistry
- energy of activation
- thermodynamic control and kinetic control of reactions.
- Reactive intermediatesGeneration, geometry, stability and reactions of carboniumions and carbanions, free radicals, carbenes, benzynes and nitrenes.
- Substitution reactions
- SN1, SN2, and SNi, mechanisms
- neighbouring group participation
- electrophilic and nucleophilic reactions of aromatic compounds including heterocyclic compounds—pyrrole, furan, thiophene and indole.
- Elimination reactions
- E1, E2 and E1cb mechanisms
- orientation in E2 reactions—Saytzeff and Hoffmann
- pyrolytic syn elimination—acetate pyrolysis, Chugaev and Cope eliminations.
- Addition reactions
- Electrophilic addition to C=C and C≡C
- nucleophilic addition to C=O, C≡N, conjugated olefins and carbonyls.
- Reactions and Rearrangements
- (a) Pinacol-pinacolone, Hoffmann, Beckmann, Baeyer-Villiger, Favorskii, Fries, Claisen, Cope, Stevens and Wagner—Meerwein rearrangements.
- (b) Aldol condensation, Claisen condensation, Dieckmann, Perkin, Knoevenagel, Witting, Clemmensen, Wolff-Kishner, Cannizzaro and von Richter reactions
- Stobbe, benzoin and acyloin condensations
- Fischer indole synthesis, Skraup synthesis, Bischler-Napieralski, Sandmeyer, Reimer-Tiemann and Reformatsky reactions.
- Pericyclic reactions
- Classification and examples
- Woodward-Hoffmann rules—electrocyclic reactions, cycloaddition reactions [2+2 and 4+2] and sigmatropic shifts [1, 3; 3, 3 and 1, 5], FMO approach.
- Preparation and Properties of PolymersOrganic polymerspolyethylene, polystyrene, polyvinyl chloride, teflon, nylon, terylene, synthetic and natural rubber.
- BiopolymersStructure of proteins, DNA and RNA.
- Synthetic Uses of ReagentsOsO₄, HIO₄, CrO₃, Pb(OAc)₄, SeO₂, NBS, B₂H₆, Na-Liquid NH₃, LiAlH₄, NaBH₄, n-BuLi, MCPBA.
- PhotochemistryPhotochemical reactions of simple organic compounds, excited and ground states, singlet and triplet states, Norrish-Type I and Type II reactions.
- Spectroscopy
- Principle and applications in structure elucidation :
- (i) Rotational—Diatomic molecules
- isotopic substitution and rotational constants.
- (ii) Vibrational—Diatomic molecules, linear triatomic molecules, specific frequencies of functional groups in polyatomic molecules.
- (iii) Electronic—Singlet and triplet states. n→π* and π→π* transitions
- application to conjugated double bonds and conjugated carbonyls Woodward-Fieser rules
- Charge transfer spectra.
- (iv) Nuclear Magnetic Resonance (¹HNMR): Basic principle
- chemical shift and spin-spin interaction and coupling constants.
- (v) Mass Spectrometry :—Parent peak, base peak, metastable peak, McLafferty rearrangement.
Syllabus as published by UPSC in the Civil Services Examination 2026 notification.