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UPSC Chemistry Optional Syllabus For IAS Exam 2025

UPSC Chemistry Optional syllabus covers a range of topics from Physical, Organic, and Inorganic Chemistry. Read on for UPSC Chemistry Optional syllabus, booklist, PYQs, and more.
authorImageAnil Solonki21 Jun, 2025
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UPSC Chemistry Optional Syllabus

 

UPSC Chemistry Optional Syllabus is a popular choice among Civil Services exam aspirants who have a strong background in the subject or engineering streams. Chemistry as an optional offers a well-structured syllabus covering Physical, Organic, and Inorganic Chemistry, blending theoretical concepts with practical applications.

The UPSC Chemistry Optional syllabus is divided into two papers, each testing candidates’ understanding of core chemistry principles, reactions, mechanisms, and analytical techniques. With a vast and static syllabus, Chemistry demands thorough preparation, consistent practice, and problem-solving skills. Candidates who master the syllabus and regularly practice numerical problems and theory-based questions often find Chemistry to be a scoring and manageable optional subject for the UPSC Mains exam.

UPSC Chemistry Optional Syllabus 2025

UPSC Chemistry Optional Syllabus 2025 broadly encompasses atomic structure, chemical bonding, thermodynamics, coordination chemistry, organic reaction mechanisms, and much more. It is divided into two papers, each carrying 250 marks, making it a total of 500 marks. 

UPSC Chemistry Optional Syllabus for Paper I

The table contains the Syllabus of UPSC Chemistry Optional Paper I:
Topic Subtopics
  • Atomic Structure
  1. 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
  1. 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.
  • Solid State
  1. 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, semiconductors.
  • Gaseous State and Transport Phenomenon
  1. Equation of state for real gases, intermolecular interactions, 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
  1. Kelvin equation; Surface tension and surface energy, wetting and contact angle, interfacial tension, and capillary action.
  • Thermodynamics
  1. Work, heat, and internal energy; first law of thermodynamics.
  2. 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, the introductory idea of the third law of thermodynamics
  • Chemical Kinetics
  1. 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
  1. Absorption of light; decay of excited state by different routes; photochemical reactions between hydrogen and halogens and their quantum yields
  • Surface Phenomena and Catalysis
  1. 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.
  • Bioinorganic Chemistry
  1. Metal ions in biological systems and their role in ion transport across the membranes (molecular mechanism), oxygen-uptake proteins, cytochrome, and ferredoxins.
 
  • Electrochemistry
 
  1. Debye-Huckel theory of strong electrolytes and Debye-Huckel limiting Law for various equilibrium and transport properties
  2. Galvanic cells, concentration cells; electrochemical series, measurement of e.m.f. of cells and its applications fuel cells and batteries
  3. Processes at electrodes; double layer at the interface; rate of charge transfer, current density; overpotential; electroanalytical techniques: amperometry, ion selective electrodes, and their uses
  • Main Group Chemistry
  1. Boranes, borazines, phosphazenes, cyclic phosphazene, silicates, 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.
  • Coordination Chemistry
  1. 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.
  2. 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.
  3. EAN rule, Synthesis structure and reactivity of metal carbonyls; carboxylate anions, carbonyl hydrides, and metal nitrosyl compounds.
  4. 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.

UPSC Chemistry Optional Syllabus for Paper II 

The table given below contains the Syllabus of UPSC Chemistry Optional Paper II:
Topic Subtopics
  • Delocalized Covalent Bonding
  1. Aromaticity, anti-aromaticity; annulenes, azulenes, tropolones, fulvenes, and sydnones.
  • (Six Sub Topic)
  • 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
  • Reactive intermediates
      • Generation, geometry, stability, and reactions of carbonium ions, carbanions, free radicals, carbenes, benzynes, and nitrenes.
    2. 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.
    3. Elimination reactions
      • E1, E2, and E1cb mechanisms; orientation in E2 reactions—Saytzeff and Hoffmann; pyrolytic syn elimination—acetate pyrolysis, Chugaev, and Cope eliminations.
    4. Addition reactions
      • Electrophilic addition to C=C and CC; nucleophilic addition to C=O, CN, conjugated olefins, and carbonyls
  • Reactions and Rearrangement
    • Pinacol-pinacolone, Hoffmann, Beckmann, Baeyer-Villiger, Favorskii, Fries, Claisen, Cope, Stevens, and Wagner—Meerwein rearrangements
    • 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
  • Spectroscopy
Principle and Applications in structure elucidation
  1. Rotational—Diatomic molecules; isotopic substitution and rotational constants.
  2. Vibrational—Diatomic molecules, linear triatomic molecules, specific frequencies of functional groups in polyatomic molecules.
  3. Electronic—Singlet and triplet states. n and transitions; application to conjugated double bonds and conjugated carbonyls Woodward-Fieser rules; Charge transfer spectra
  4. Nuclear Magnetic Resonance (1H NMR): Basic principle; chemical shift and spin-spin interaction and coupling constants.
  5. Mass Spectrometry:—Parent peak, base peak, metastable peak, McLafferty rearrangement.
  • Photochemistry
  1. Photochemical reactions of simple organic compounds, excited and ground states, singlet and triplet states, Norrish-Type I and Type II reactions
 
  • Preparation and Properties of Polymers
 
  1. Organic polymers polyethylene, polystyrene, polyvinyl chloride, Teflon, nylon, terylene, synthetic and natural rubber,
  2. Biopolymers: Structure of proteins, DNA, and RNA
 
  • Synthetic Uses of Reagent
 OsO4, HlO4, CrO3, Pb(OAc)4, SeO2, NBS, B2H6, Na-Liquid NH3, LiAIH4, NaBH4, n-BuLi, MCPBA
  • Pericyclic reactions
  1. 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

UPSC Exam Pattern of Chemistry Optional

The UPSC exam pattern of Chemistry Optional is as follows:
  • The UPSC main exam is divided into two papers i.e. Paper-1 and Paper-2.
  • Both Paper I and Paper II carry 250 marks each, making the total of 500 marks for the Chemistry optional papers.
  • In both Paper I and Paper II of Chemistry Optional candidates have to attempt FIVE questions in all. THREE hours are allotted to attempt each paper.
  • Question Number 1 and Question Number 5 from both papers are compulsory to attempt and out of the remaining questions, THREE are to be attempted choosing at least ONE question from each Section.
UPSC Chemistry Optional Exam Pattern
Particular Details
Total Papers Two, Paper I and Paper II
Total Marks 500 (250 Each)
Time allowed 3 Hours for each paper
Sections Section A and Section B
Questions Total 8 questions with subparts
Compulsory Question Question No. 1 and 5
Marks Distribution 10, 15, and 20 marker questions

UPSC Chemistry Optional Book List

The table below contains the Book List for UPSC Chemistry Optional for Physical, Organic and Inorganic branches of Chemistry:
UPSC Chemistry Optional Books
Branch Book Title Author(s)
Physical Chemistry Books Principles of Physical Chemistry Puri, Sharma, and Pathway
Advanced Physical Chemistry Gurdeep Raj
A Textbook of Physical Chemistry – Vol. 4 Kapoor K L
An Introduction to Electrochemistry Samuel Glasstone
Inorganic Chemistry Books Principles of Inorganic Chemistry Puri, Sharma, and Kalia
Concise Inorganic Chemistry J.D. Lee
Selected Topics in Inorganic Chemistry Malik, Madan, and Tuli
Organic Chemistry Books Advanced Organic Chemistry Francis A. Carey and Richard J. Wothers
Organic Chemistry Clayden, Nick Greeves, and S. Warren
Principle of Organic Synthesis Norman and Coxon
Advanced Organic Chemistry : Reactions, Mechanisms, And Structure Michael B. Smith, Jerry March
Organic Spectroscopy William Kemp
Reaction Mechanism in Organic Chemistry Mukherjee and Singh
Organic Chemistry Stanley H. Pine
Spectroscopy of Organic Compounds P. S. Kalsi

UPSC Chemistry Optional Paper PYQs

The table contains the list of UPSC Chemistry Optional Papers I and II of Previous years:
UPSC Chemistry Optional Paper 2024
 Chemistry Optional Paper I  Chemistry Optional Paper II
 UPSC Chemistry Optional Paper 2023
Chemistry Optional Paper I Chemistry Optional Paper II
UPSC Chemistry Optional Paper 2022
Chemistry Optional Paper I Chemistry Optional Paper II
UPSC Chemistry Optional Paper 2021
Chemistry Optional Paper I Chemistry Optional Paper II
UPSC Chemistry Optional Paper 2020
Chemistry Optional Paper I Chemistry Optional Paper II

How to Prepare for UPSC Chemistry Optional?

Preparing for the Chemistry Optional paper in the UPSC (Union Public Service Commission) exam requires a strategic approach and dedicated effort. Here's a comprehensive guide to help you prepare effectively:
  1. Understand the Syllabus: Familiarise yourself with the UPSC Chemistry Optional syllabus. It will help you identify the important topics and plan your preparation accordingly.
  2. Refer to Standard Books: Utilise standard textbooks recommended for undergraduate and postgraduate studies in chemistry.
  3. Join Mock Tests: Regularly take mock tests and simulate exam conditions to assess your progress and identify areas that need improvement.
  4. Make Short Notes: Prepare concise notes while studying each topic. These notes will serve as a quick revision aid during the final days before the exam.
  5. Focus on Conceptual Understanding: Instead of rote memorization, focus on understanding the underlying concepts of each topic. This will help you tackle questions from diverse angles.
  6. Current Affairs: Stay updated with recent developments in the field of chemistry, especially those relevant to the UPSC syllabus. This can include advancements in research, discoveries, and applications.
  7. Revision: Allocate sufficient time for revision. Regularly revise the topics you've covered to reinforce your understanding and retention.

UPSC Chemistry Optional Success Rate

The table below contains the list of Number of Candidates who have cleared as compared to total candidates, along with the success rate:
UPSC Chemistry Optional Success Rate
Year Total Candidates No. of Candidates cleared (Success Rate)
2016 124 7 (5.64%)
2015 92 11 (11.95%)
2014 98 7 (7.14%)
2013 85 6 (7.05%)
2012 104 11 (10.57%)
2011 123 11 (8.94%)
2010 107 7 (6.54%)

UPSC Chemistry Optional Toppers

The table below contains the list of toppers in Chemistry Optional in UPSC from previous years:
UPSC Chemistry Optional Toppers
S. No. Name Year (Rank)
1 Nitish Maurya 2022 (Rank 90)
2 Pankaj Verma 2022 (Rank 515)
3 Deepesh Kedia 2017 (Rank 221)
4 Rahul Gupta 2016 (Rank 182)
5 Charchit Gaur 2015 (Rank 96)
6 Pulkit Garg 2015 (Rank 27)
7 Ankur Garg 2002 (Rank 1)

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UPSC Chemistry Optional Syllabus FAQs

Is chemistry good optional for UPSC?

Yes, Chemistry is a good UPSC optional for candidates with a science background due to its scoring potential and clear concepts.

Who got highest marks in chemistry optional UPSC?

Ankur Garg who got the first rank in the year 2002, has got the highest marks in Chemistry Optional.

What is the success rate of UPSC chemistry optional?

According to data from the last five years, around 100 to 150 aspirants opt for Chemistry optional with a success rate hovering between 9 to 10 percent.

Is Chemistry difficult for UPSC?

Mastering Chemistry demands strong theoretical understanding and grasp of complex concepts, making it moderately challenging due to its broad and detailed syllabus.

Is Chemistry a scoring subject in UPSC?

Yes, Chemistry is considered a scoring subject in UPSC with focused preparation and clear conceptual understanding.
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