There are two papers in the IAS (UPSC CSE) Main Exam, and the chemistry optional is a scoring option. The syllabus is suitable for those who have graduated in Chemistry. Each paper is for 250 marks and has to attempted in 3 hours.

The UPSC Chemistry syllabus covers fundamental chemistry topics, hence candidates must understand the fundamental concepts. The atomic structure, states of matter, and various types of reactions are just a few of the topics covered in the Chemistry optional syllabus.

1.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.
2.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.
3.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.
4.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.
5.Liquid State :
Kelvin equation; Surface tension and surface enercy, wetting and contact angle, interfacial tension and capillary action.
6.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, and ; 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.
7.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.
8.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.
9.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.
10.Photochemistry:
Absorption of light; decay of excited state by different routes; photochemical reactions between hydrogen and halogens and their quantum yields.
11.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.
12.Bio-inorganic chemistry:
Metal ions in biological systems and their role in ion-transport across the membranes (molecular mechanism), oxygen-uptake proteins, cytochromes and ferrodoxins.
13.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 elctronic 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.
14.Main Group Chemistry:
Boranes, borazines, phosphazenes and cyclic phosphazene, silicates and silicones, Interhalogen compounds; Sulphur—nitrogen compounds, noble gas compounds.
15.General Chemistry of ‘f’ Block Element:
Lanthanides and actinides: separation, oxidation states, magnetic and spectral properties; lanthanide contraction.

1.Delocalised covalent bonding :
Aromaticity, anti-aromaticity; annulenes, azulenes, tropolones, fulvenes, sydnones.
2.(i)Reaction mechanisms : General methods (both kinetic and non-kinetic) of study of mechanisms or organic reactions : isotopies, mathod cross-over experiment, intermediate trapping, stereochemistry; energy of activation; thermodynamic control and kinetic control of reactions.
(ii)Reactive intermediates : Generation, geometry, stability and reactions of carboniumions and carbanions, free radicals, carbenes, benzynes and nitrenes.
(iii)Substitution reactions :—SN 1, SN 2, and SN i, mechanisms ; neighbouring group participation; electrophilic and nucleophilic reactions of aromatic compounds including heterocyclic compounds—pyrrole, furan, thiophene and indole.
(iv)Elimination reactions :—E1, E2 and E1cb mechanisms; orientation in E2 reactions— Saytzeff and Hoffmann; pyrolytic syn elimination—acetate pyrolysis, Chugaev and Cope eliminations.
(v)Addition reactions :—Electrophilic addition to C=C and CC; nucleophilic addition to C=O, CN, conjugated olefins and carbonyls.
(vi)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.
3.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.
4.(i)Preparation and Properties of Polymers: Organic polymerspolyethylene, polystyrene, polyvinyl chloride, teflon, nylon, terylene, synthetic and natural rubber.
(ii)Biopolymers: Structure of proteins, DNA and RNA.
5.Synthetic Uses of Reagents:
OsO4, HlO4, CrO3, Pb(OAc)4, SeO2, NBS, B2H6, Na-Liquid NH3, LiAIH4, NaBH4, n-BuLi, MCPBA.
6.Photochemistry :—Photochemical reactions of simple organic compounds, excited and ground states, singlet and triplet states, Norrish-Type I and Type II reactions.
7.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.