Indian National Chemistry Olympiad (INChO)


Quick Fact: Scoring top ranks in the INChO can lead you to the IChO (International Chemistry Olympiad). 


To all the students who enjoy studying Chemistry, here is an olympiad for you. The Indian National Chemistry Olympiad or INChO is an annual competition held among high school students. It is a unique opportunity for every student to gain more knowledge and experience in Chemistry. You will be able to connect with students from all over India and even from around the world (if you qualify for IChO). The Indian National Chemistry Olympiad (INChO) is conducted by HBCSE (Homi Bhabha Centre for Science Education). 


Road to IChO (Until 2020)

To help you understand further how the Indian National Chemistry Olympiad (INChO) plays an important role for you, here are the different exams that a student needs to clear/qualify for International Chemistry Olympiad (IChO). 


Stage 1: National Standard Examination in Chemistry (NSEC)

Students of Class 11 and Class 12 participate in this examination in the month of November every year. 


Stage 2: Indian National Chemistry Olympiad (INChO)

Students who clear the NSEC (generally top 300 students) appear for the INChO. This exam is organised by HBCSE in 15 centres all across India. Those who clear this examination get a certificate from the Association of Chemistry Teachers (ACT) which is a prestigious achievement in itself. 


Stage 3: Orientation cum Selection Camp (OCSC) in Chemistry 

The top 35 students are chosen from the examination results of INChO and they are invited to attend an orientation camp at the HBCSE centre. They have to pass several tests here in the camp. 


Stage 4: Pre-Departure Training (PDT) Camp for IChO

5-6 students are selected and given special training for the international olympiad. 


Stage 5: International Chemistry Olympiad (IChO)

The 5 students along with 2 teachers and 1 scientific observer represent India at the IChO. 


Road to IChO: Introduction of Indian Olympiad Qualifier for Chemistry (IOQC) (for 2021-2022 session)

The above-stated stages were a part of the usual procedure followed until 2020. For the 2021-2022 session, only one qualifier examination was conducted known as the Indian Olympiad Qualifier for Chemistry (IOQC). The IOQC examination was conducted in two parts. 

  • Indian Olympiad Qualifier in Chemistry (IOQC) was held on 20 March 2022 (Sunday), 14:30 – 18:00 hrs.
  • Further selection stages beyond IOQ, namely the Orientation-cum-Selection Camps (OCSCs), were cancelled (the International Olympiad for Chemistry was scheduled for July-August). Selection for the Indian team in Chemistry was based on the performance in IOQ Part II. 
  • 5 students at the top of the merit list of IOQC Part II were to be selected for the Indian team to the International Chemistry Olympiad (IChO) 2022.


Indian Olympiad Qualifier in Chemistry (IOQC) 2021-2022

The Indian Olympiad Qualifier in Chemistry (IOQC) constitutes two examinations - National Standard Examination (NSEC) and Indian National Olympiad (INChO). In other words:

  • IOQC Part I is also known as NSEC 
  • IOQC Part II is also known as INChO 


National Standard Examination (NSEC)

Duration: 75 Minutes 

Objective-type questions 

This is a screening examination for selective evaluation of the second part, that is, INChO/ IOQC Part II. 

Indian National Olympiad (INChO)

Duration 120 minutes

Detailed questions 


The IOQC is jointly organised by the Association of Chemistry Teachers (ACT) and Homi Bhabha Centre for Science Education (Tata Institute of Fundamental Research) – HBCSE (TIFR). The academic responsibility of Part I: NSEC will be borne by ACT while that of Part II: INO will be borne by HBCSE. The remaining stages of the Olympiad programme will be carried out by HBCSE.


Eligibility for IOQC 2021-2022

The eligibility criteria for Indian Olympiad Qualifier in Chemistry (IOQC) 2021-2022 include the following: 

  • The students must be eligible to hold an Indian passport. 
  • The date of birth of the student should be between 1 July 2002 and 30 June 2007, both days inclusive. 
  • The student must be residing and studying in India since 30 November 2019 or earlier or must be studying in an Indian school system since 30 November 2019 or earlier. 
  • The student must be studying in classes 8, 9, 10, 11, or 12, and not have completed (or scheduled to complete) class 12 board examinations earlier than 30 November 2021. Must not have commenced (or planning to commence) studies in a university or equivalent institution by 1 June 2022. 
  • The student must not be appearing in IOQJS 2021-2022.


INChO Syllabus 

  1. Some Basic Concepts of Chemistry 
  • General Introduction: Importance and scope of chemistry. Nature of matter, laws of chemical combination, Dalton's atomic theory: concept of elements, atoms and molecules. 
  • Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula, chemical reactions, stoichiometry and calculations based on stoichiometry.


  1. Structure of Atom 
  • Bohr's model and its limitations, concept of shells and subshells, dual nature of matter and light, de Broglie's relationship, Heisenberg uncertainty principle, concept of orbitals, quantum numbers, shapes of s, p and d orbitals, rules for filling electrons in orbitals - Aufbau principle, Pauli's exclusion principle and Hund's rule, electronic configuration of atoms, stability of half-filled and completely filled orbitals.


  1. Classification of Elements and Periodicity in Properties
  • Modern periodic law and the present form of periodic table, periodic trends in properties of elements -atomic radii, ionic radii, inert gas radii, Ionization enthalpy, electron gain enthalpy, electronegativity, valency. Nomenclature of elements with atomic number greater than 100


  1. Chemical Bonding and Molecular structure 
  • Valence electrons, ionic bond, covalent bond, bond parameters, Lewis structure, polar character of covalent bond, covalent character of ionic bond, valence bond theory, resonance, geometry of covalent molecules, VSEPR theory, concept of hybridization, involving s, p and d orbitals and shapes of some simple molecules, molecular orbital theory of homonuclear diatomic molecules (qualitative idea only), hydrogen bond. 


  1. States of Matter: Gases and Liquids 
  • Three states of matter, intermolecular interactions, types of bonding, melting and boiling points, role of gas laws in elucidating the concept of the molecule, Boyle's law, Charles law, Gay Lussac's law, Avogadro's law, ideal behaviour, empirical derivation of gas equation, Avogadro's number, ideal gas equation. 
  • Deviation from ideal behaviour, liquefaction of gases, critical temperature, kinetic energy and molecular speeds (elementary idea)
  • Liquid State: vapour pressure, viscosity and surface tension (qualitative idea only, no mathematical derivations) 


  1. States of Matter: Solid State 
  • Classification of solids based on different binding forces: molecular, ionic, covalent and metallic solids, amorphous and crystalline solids (elementary idea). Unit cell in two dimensional and three dimensional lattices, calculation of density of unit cell, packing in solids, packing efficiency, voids, number of atoms per unit cell in a cubic unit cell, point defects.


  1. Chemical Thermodynamics 
  • Concepts of System and types of systems, surroundings, work, heat, energy, extensive and intensive properties, state functions. 
  • First law of thermodynamics-internal energy and enthalpy, heat capacity and specific heat, measurement of ∆U and ∆H, Hess's law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomization, sublimation, phase transition, ionization, solution and dilution. 
  • Second law of Thermodynamics (brief introduction).Introduction of entropy as a state function, Gibb's energy change for spontaneous and non- spontaneous processes, criteria for equilibrium. 
  • Third law of thermodynamics (brief introduction). 


  1. Equilibrium 
  • Equilibrium in physical and chemical processes, dynamic nature of equilibrium, law of mass action, equilibrium constant, factors affecting equilibrium- Le Chatelier's principle, ionic equilibrium- ionization of acids and bases, strong and weak electrolytes, degree of ionization, ionization of poly basic acids, acid strength, concept of pH, Henderson Equation, hydrolysis of salts (elementary idea), buffer solution, solubility product, common ion effect (with illustrative examples). 


  1. Solutions 
  • Types of solutions, expression of concentration of solutions of solids in liquids, solubility of gases in liquids, solid solutions, colligative properties - relative lowering of vapour pressure, Raoult's law, elevation of boiling point, depression of freezing point, osmotic pressure, determination of molecular masses using colligative properties, abnormal molecular mass, Van't Hoff factor.


  1. Electrochemistry 
  • Redox reactions: Concept of oxidation and reduction, oxidation number, balancing redox reactions, in terms of loss and gain of electrons and change in oxidation number, applications of redox reactions. 
  • Conductance in electrolytic solutions, specific and molar conductivity, variations of conductivity with concentration, Kohlrausch's Law, electrolysis and law of electrolysis (elementary idea), dry cell-electrolytic cells and Galvanic cells, lead accumulator, EMF of a cell, standard electrode potential, Nernst equation and its application to chemical cells, Relation between Gibbs energy change and EMF of a cell, fuel cells, corrosion. 


  1. Chemical Kinetics 
  • Rate of a reaction (Average and instantaneous), factors affecting rate of reaction: concentration, temperature, catalyst; order and molecularity of a reaction, rate law and specific rate constant, integrated rate equations and half-life (only for zero and first order reactions), concept of collision theory (elementary idea, no mathematical treatment). 
  • Activation energy, Arrhenius equation.


  1. Surface Chemistry
  • Adsorption - physisorption and chemisorption, factors affecting adsorption of gases on solids, catalysis, homogenous and heterogenous activity and selectivity; enzyme catalysis colloidal state distinction between true solutions, colloids and suspension; lyophilic, lyophobic multi-molecular and macromolecular colloids; properties of colloids; Tyndall effect, Brownian movement, electrophoresis, coagulation, emulsion - types of emulsions.


  1. s-Block Elements (Alkali and Alkaline Earth Metals) 
  • Position of hydrogen in periodic table, occurrence, isotopes, preparation, properties and uses of hydrogen, hydrides-ionic covalent and interstitial; physical and chemical properties of water, heavy water, hydrogen peroxide - preparation, reactions and structure and use; hydrogen as a fuel. 
  • Group 1 and Group 2 Elements General introduction, electronic configuration, occurrence, anomalous properties of the first element of each group, diagonal relationship, trends in the variation of properties (such as ionization enthalpy, atomic and ionic radii), trends in chemical reactivity with oxygen, water, hydrogen and halogens, uses. 
  • Preparation and properties of some important compounds: Sodium Carbonate, Sodium Chloride, Sodium Hydroxide and Sodium Hydrogencarbonate, Biological importance of Sodium and Potassium. Calcium Oxide and Calcium Carbonate and their industrial uses, biological importance of Magnesium and Calcium. 


  1. p -Block Elements 
  • General Introduction to p -Block Elements 
  • Group 13 Elements: General introduction, electronic configuration, occurrence, variation of properties, oxidation states, trends in chemical reactivity, anomalous properties of first element of the group, 
  • Boron - physical and chemical properties, some important compounds, Borax, Boric acid, Boron Hydrides, Aluminium: Reactions with acids and alkalies, uses. 
  • Group 14 Elements: General introduction, electronic configuration, occurrence, variation of properties, oxidation states, trends in chemical reactivity, anomalous behaviour of first elements. 
  • Carbon-catenation, allotropic forms, physical and chemical properties; uses of some important compounds: oxides. Important compounds of Silicon and a few uses: Silicon Tetrachloride, Silicones, Silicates and Zeolites, their uses. 
  • Group -15 Elements: General introduction, electronic configuration, occurrence, oxidation states,  trends in physical and chemical properties; Nitrogen preparation properties and uses; compounds of  Nitrogen: preparation and properties of Ammonia and Nitric Acid. 
  • Group 16 Elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties, dioxygen: Preparation, Properties and uses, classification of Oxides, Ozone, Sulphur -allotropic forms; compounds of Sulphur: Preparation Properties and uses of Sulphur-dioxide, Sulphuric Acid: industrial process of manufacture, properties and uses; Oxoacids of Sulphur (Structures only).
  • Group 17 Elements: General introduction, electronic configuration, oxidation states, occurrence, trends in physical and chemical properties; compounds of halogens, Preparation, properties and uses of Chlorine and Hydrochloric acid, interhalogen compounds, Oxoacids of halogens (structures only). 
  • Group 18 Elements: General introduction, electronic configuration, occurrence, trends in physical and chemical properties, uses. 


  1. ‘d’ and ‘f’ Block Elements 
  • General introduction, electronic configuration, occurrence and characteristics of transition metals, general trends in properties of the first row transition metals - metallic character, ionization enthalpy, oxidation states, ionic radii, colour, catalytic property, magnetic properties, interstitial compounds, alloy formation, preparation and properties of K2Cr2O7 and KMnO4. 
  • Lanthanoids - Electronic configuration, oxidation states, chemical reactivity and lanthanoid contraction and its consequences. 
  • Actinoids - Electronic configuration, oxidation states and comparison with lanthanoids.


  1. General Principles and Processes of Isolation of Elements 
  • Principles and methods of extraction - concentration, oxidation, reduction-electrolytic method and refining; occurrence and principles of extraction of aluminium, copper, zinc and iron


  1. Coordination Compounds 
  • Coordination compounds - Introduction, ligands, coordination number, colour, magnetic properties and shapes, IUPAC nomenclature of mononuclear coordination compounds. Bonding, Werner's theory, VBT, and CFT; structure and stereoisomerism, importance of coordination compounds (in qualitative inclusion, extraction of metals and biological systems).


  1. Organic Chemistry - Some Basic Principles and Techniques 
  • General introduction, methods of purification, qualitative and quantitative analysis, classification and IUPAC nomenclature of organic compounds. 
  • Electronic displacements in a covalent bond: inductive effect, electromeric effect, resonance and hyperconjugation. Homolytic and heterolytic fission of a covalent bond: free radicals, carbocations, carbanions, electrophiles and nucleophiles, types of organic reactions.


  1. Hydrocarbons 
  • Classification of Hydrocarbons 
  • Aliphatic Hydrocarbons: Alkanes - Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions including free radical mechanisms of halogenation, combustion and pyrolysis. 
  • Alkenes - Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markovnikov's addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition. 
  • Alkynes - Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical reactions: acidic character of alkynes, addition reaction of - hydrogen, halogens, hydrogen halides and water.
  • Aromatic Hydrocarbons: Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Crafts alkylation and acylation, and the direct influence of functional groups in monosubstituted benzene. Carcinogenicity and toxicity. 


  1. Haloalkanes and Haloarenes 
  • Haloalkanes: Nomenclature, nature of C-X bond, physical and chemical properties, mechanism of substitution reactions, optical rotation. 
  • Haloarenes: Nature of C-X bond, substitution reactions (Directive influence of halogen in monosubstituted compounds only). Uses and environmental effects of - dichloromethane, trichloromethane, tetrachloromethane, iodoform, freons, DDT. 


  1. Alcohols, Phenols and Ethers 
  • Alcohols: Nomenclature, methods of preparation, physical and chemical properties (of primary alcohols only), identification of primary, secondary and tertiary alcohols, mechanism of dehydration, uses with special reference to methanol and ethanol. 
  • Phenols: Nomenclature, methods of preparation, physical and chemical properties, acidic nature of phenol, electrophilic substitution reactions, uses of phenols. 
  • Ethers: Nomenclature, methods of preparation, physical and chemical properties, uses.


  1. Aldehydes, Ketones and Carboxylic Acids 
  • Aldehydes and Ketones: Nomenclature, nature of carbonyl group, methods of preparation, physical and chemical properties, mechanism of nucleophilic addition, reactivity of alpha hydrogen in aldehydes, uses. 
  • Carboxylic Acids: Nomenclature, acidic nature, methods of preparation, physical and chemical properties; uses.


  1. Organic compounds containing Nitrogen 
  • Amines: Nomenclature, classification, structure, methods of preparation, physical and chemical properties, uses, identification of primary, secondary and tertiary amines. 
  • Cyanides and Isocyanides - preparation and reactions. Diazonium salts: Preparation, chemical reactions and importance in synthetic organic chemistry.


  1. Biomolecules 
  • Carbohydrates - Classification (aldoses and ketoses), monosaccharides (glucose and fructose), D-L configuration oligosaccharides (sucrose, lactose, maltose), polysaccharides (starch, cellulose, glycogen); Importance of carbohydrates. 
  • Proteins - Elementary idea of - amino acids, peptide bond, polypeptides, proteins, structure of proteins - primary, secondary, tertiary structure and quaternary structures (qualitative idea only), denaturation of proteins; enzymes. Hormones - Elementary idea excluding structure. Vitamins - Classification and functions. 
  • Nucleic Acids: DNA and RNA. 


  1. Polymers 
  • Copolymerization, some important polymers: natural and synthetic like polythene, nylon, polyesters, bakelite, rubber. Biodegradable and non- biodegradable polymers.


  1. Environmental Chemistry 
  • Environmental pollution - air, water and soil pollution, chemical reactions in atmosphere, smog, major atmospheric pollutants, acid rain, ozone and its reactions, effects of depletion of ozone layer, greenhouse effect and global warming- pollution due to industrial wastes, green chemistry as an alternative tool for reducing pollution, strategies for control of environmental pollution. 


  1. Chemistry in Everyday Life 
  • Chemicals in medicines - analgesics, tranquillisers, antiseptics, disinfectants, antimicrobials, antifertility drugs, antibiotics, antacids, antihistamines. Chemicals in food - preservatives, artificial sweetening agents, elementary idea of antioxidants.Cleansing agents- soaps and detergents, cleansing action.


*Note: The above syllabus has been taken from


INChO Past Papers 

INChO Past Year Paper






2013 2014 2015
2016 2017







Books for INChO 





Books for Organic Chemistry

Organic Chemistry, 6th Edition

Morrison & Boyd

Prentice Hall of India Pvt. Ltd. New Delhi

Organic Chemistry, 3rd Edition


The McGraw-Hill Companies, Inc.

Organic Chemistry-a brief course, 2nd Edition

Atkins & Carey

The McGraw-Hill Companies, Inc.

Books for Inorganic Chemistry

Concise Inorganic Chemistry, 5th Edition


ELBS with Chapman & Hall

Basic Inorganic Chemistry, 3rd Edition

Cotton, Wilkinson &Gaus

John Wiley & Sons

Books for Analytical Chemistry

Analytical Chemistry, 5th Edition


John Wiley & Sons, Inc

Fundamentals of Analytical Chemistry, 2nd Edition

Skoog & West

Holt International Edition

Principles of Instrumental Analysis, 3rd Edition


Holt-Saunders International Edition

Books for Biochemistry

Principles of Biochemistry*


CBS publishers and distributors Pvt. Ltd. Delhi

Biochemistry an Introduction, 2nd Edition

Mckee & Mckee


Books for General Chemistry

Analytical Chemistry, 5th Edition


John Wiley & Sons, Inc

Fundamentals of Analytical Chemistry, 2nd Edition


Holt International Edition

Schaum’s- series books on problems in various disciplines of chemistry


Books for Practical Chemistry

Vogel's Textbook of Quantitative Chemical Analysis, 5th Edition

Jeffrey, Bassett, Mendham & Denney

ELBS with Longman

Elementary Practical Organic Chemistry (Part 1, 2 and 3)

Arthur I. Vogel

CBS Publishers and Distributors, Delhi

Techniques and Experiments for Organic Chemistry, 6th Edition

Addison Ault

University Science Books, Sausalito, California

Quantitative Analysis, 5th Edition

Day & Underwood

Prentice Hall of India Pvt. Ltd. New Delhi

CBSE practical books



How can askIITians help you prepare for INChO 2022-2023?

The final dates for INChO 2022-2023 are not yet revealed by HBCSE. But, the students must start preparing for it as the exam is going to be extremely competitive. The askIITians team can help you with the study material required for INChO, previous year papers, sample papers, daily practice worksheets, revision notes and a lot more. Our Chemistry experts will guide you step by step and help you ace this olympiad. Contact us today for more information. 


Frequently Asked Questions 


  1. What is IOQC? 

For the 2021-2022 session of INChO, only one qualifier examination was conducted known as the Indian Olympiad Qualifier for Chemistry (IOQC). This examination had two parts: Part 1: National Standard Examination for Chemistry (NSEC) and Part 2: Indian National Chemistry Olympiad (INChO). 


  1. What is INChO? 

INChO or Indian National Chemistry Olympiad is a qualifying examination for International Chemistry Olympiad Training Camp. The selected students from the camp appear in the International Chemistry Olympiad. 


  1. Who can help me prepare for INChO? 

askIITians team is here to guide students on how to study effectively for INChO and achieve a higher rank (amongst the top 30). We provide complete study resources for INChO. 


  1. When will INChO 2022-2023 be held? 

The dates are not yet revealed by HBCSE. Stay tuned to the askIITians website to know more about INChO 2022-2023. 


  1. What will be the process of INChO in 2022-2023? 

There is no clear indication whether the 5-stage process will be followed in the 2022-2023 session or not. We must wait until the final notification arrives from HBCSE. 


Upto 50% Scholarship on Live Classes

Course Features

  • Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution