Chemistry Optional

How to prepare for chemistry optional?

Chemistry is one of the core subjects of science. It is chosen by candidates with a science background at graduation level. Chemistry optional being a science subject has concise topics and answers to the questions asked are to be answered in a precise manner. Also there is little scope subjectivity involved by examiner. Unlike humanities subjects wherein long answers are needed to address the questions, answers for chemistry questions are straightforward and to the point.Also many topics are related to current affair as well. Here are some preparation strategies which can be adopted by the candidates while preparing for chemistry optional subject:

  1. The first and foremost thing is to understand the syllabus of UPSC for chemistry optional. A basic understanding of syllabus is required in order to know what are the different areas required to be covered during preparation. A best way to be well versed with the syllabus is to write it down and stick it to the study table where you study on a daily basis. This will act as a reminder as how much syllabus you need to cover and how much you have already covered and require less attention.
  2. There are two optional paper carrying 250marks each. Hence total weight age of 500marks. This shows that chemistry optional contains a lot of marks hence it requires rigorous of practice.
  3. One of the major branches in paper I of chemistry optional is physical chemistry and inorganic chemistry. Both are equally important and all fundamentals and basics should be covered while doing preparation.
  4. There are direct and straightforward questions asked in the paper. Such question requires a precise answer with proper formulas. Many a time’s numerical questions are also asked from thermodynamics, photochemistry, electrochemistry etc. For these kinds of questions practice of numerical beforehand is needed. Practice as many numerical as much you can in order to solve them faster in the final exam.
  5. It is recommended to study lengthy questions. Prepare a list of topics which can come as lengthy questions. Practice them thoroughly multiple times in order to gain clarity of the topic. And if question comes in the exam from that particular topic, a candidate can easily score well in that answer.

Also it can be solved faster since that topic has already been covered during preparation and can be answered faster which will in turn help to solve the paper faster and time saved can be used for answering the remaining questions.

  1. Paper II covers the organic chemistry. This is one of the most scoring portions of the exam. Since it contains numerical problems, objective and factual questions. In this a candidate can easily gain marks by being well versed with the formulas and other fundamentals of organic chemistry.
  2. Candidates with graduation in chemistry need to focus and prepare the areas of chemistry optional which were not covered during the time of graduation. After finishing these uncovered topics a candidate can complete the remaining portion of the syllabus. In this way whole of the syllabus will be completed faster and more time will be left for revision.
  3. Chemistry optional being a science subject, the syllabus is very well defined. So a candidate needs to stick to the syllabus and prepare accordingly.
  4. The questions asked in chemistry optional are straightforward so it is better to write answers precisely by including all the relevant content. This will help you to fetch more marks. Also use diagrams where ever required. This enhances the quality of your answer.


chemistry Optional



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, the 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 energy, wetting and contact angle, interfacial tension and capillary action.

6. Thermodynamics: Work, heat and internal energy; first law of thermodynamics. The 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, a and b; J-T effect and inversion temperature; criteria for equilibrium, the relation between equilibrium constant and thermodynamic quantities; Nernst heat theorem, the introductory idea of the 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; the rate of charge transfer, current density; overpotential; electroanalytical techniques: amperometry, ion-selective electrodes and their use.148 THE GAZETTE OF INDIA: EXTRAORDINARY [PART I—SEC. 1]

 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: Absorption 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 ferredoxins.

13. Coordination Chemistry : (i) Bonding in the 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.

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, method cross-over experiment, intermediate trapping, stereochemistry; the energy of activation; thermodynamic control and kinetic control of reactions. (ii) Reactive intermediates: Generation, geometry, stability and reactions of carbenium ions 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, Chagaev and Cope eliminations. (v) Addition reactions:—Electrophilic addition to C=C and CºC; nucleophilic addition to C=O, CºN, 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 polymers polyethene, 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®p* and p®p* 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.