INChO: syllabus, mock tests and practice
Indian National Chemistry Olympiad — Stage 2 of India's Science Olympiad programme in Chemistry, conducted by HBCSE. Top scorers qualify for the Orientation-cum-Selection Camp (OCSC), from which 4 students are chosen to represent India at the International Chemistry Olympiad (IChO). For students in Class X, XI and XII.
- Classes
- Grade 10, Grade 11, Grade 12
- Syllabus years
- 2026-27
- Mock tests
- 13
- Downloads
- 38
About the INChO exam
How the exam works
INChO is the national second-stage Chemistry Olympiad. Entry comes through NSEC qualification and any officially permitted exemptions. HBCSE administers this stage; qualifying students may proceed to the Orientation-cum-Selection Camp and later team selection. The announced 2027 examination lasts three hours.
Who can apply
The IAPT 2026–27 portal lists Senior Science birth dates 1 July 2007–30 June 2012 and Classes 10–12, subject to the full current eligibility rules. For INO, the official brochure's nationality/residency, school and university conditions and any later amendments also apply. An age/class match alone does not guarantee eligibility.
When it happens
NSEC: 22 November 2026, 11:30–13:30 IST. INChO: 30 January 2027, 13:30–16:30 IST. HBCSE says senior INO selection lists will be published by 15 January 2027, followed by mandatory HBCSE registration. NSE enrolment for this cycle is closed. Checked 1 November 2026.
How to register
For the NSE stage, register through an approved centre or IAPT's self-enrolment portal during the published window; the 2026 fee was ₹300 per subject. Keep personal/parent details, school details and valid identity proof ready. This cycle's entry window is closed. Shortlisted senior candidates must register separately on HBCSE's INO site after the selection list; failure to register can disqualify an otherwise selected student.
Official website, syllabus and past papers
Senior science syllabuses broadly extend through CBSE Class 12, with supporting mathematics. Astronomy emphasises physics, mathematics and elementary astronomy. Include foundational material from earlier classes.
INChO syllabus
INChO syllabus, All classes · 2026-27
Physical Chemistry
- Basic Concepts of Chemistry: Study the nature of matter, laws of chemical combination, Dalton's atomic theory, atomic and molecular masses, and the mole concept. Calculate percentage composition, empirical and molecular formulae and do stoichiometry.
- Structure of Atom: Study Bohr's model and its limits, dual nature of matter, de Broglie's relation and the uncertainty principle. Learn orbitals, quantum numbers, orbital shapes, the Aufbau principle, Pauli's exclusion principle, Hund's rule and electronic configurations.
- Classification of Elements and Periodicity: Learn the modern periodic law and the periodic table. Study trends in atomic and ionic radii, ionization enthalpy, electron gain enthalpy, electronegativity and valency.
- Chemical Bonding and Molecular Structure: Study ionic and covalent bonds, bond parameters, Lewis structures, polarity, valence bond theory and resonance. Predict shapes using VSEPR and hybridization, and learn molecular orbital theory of homonuclear diatomics and hydrogen bonding.
- States of Matter: Gases and Liquids: Study intermolecular interactions and the gas laws leading to the ideal gas equation. Learn deviations from ideal behaviour, liquefaction, critical temperature, molecular speeds, and qualitative ideas on vapour pressure, viscosity and surface tension.
- States of Matter: Solid State: Classify solids by binding forces and as amorphous or crystalline. Study unit cells, packing efficiency, voids, density calculations and point defects.
- Chemical Thermodynamics: Learn systems, state functions, internal energy and enthalpy, heat capacity, Hess's law and various enthalpies. Study entropy, Gibbs energy and spontaneity, and the second and third laws briefly.
- Chemical and Ionic Equilibrium: Study dynamic equilibrium, the law of mass action, equilibrium constants and Le Chatelier's principle. Learn ionization of acids and bases, pH, buffers, the Henderson equation, salt hydrolysis, solubility product and the common ion effect.
- Solutions: Study ways of expressing concentration, solubility of gases, and solid solutions. Learn colligative properties, Raoult's law, molecular mass determination, abnormal molecular masses and the van't Hoff factor.
- Redox Reactions: Understand oxidation and reduction in terms of electron transfer and oxidation number. Practise balancing redox equations and learn their applications.
- Electrochemistry: Study conductance, molar conductivity, Kohlrausch's law and electrolysis. Learn galvanic cells, electrode potentials, the Nernst equation, the link between Gibbs energy and EMF, batteries, fuel cells and corrosion.
- Chemical Kinetics: Study rates of reaction and the factors affecting them, order, molecularity and rate laws. Use integrated rate equations and half-life for zero and first order reactions, collision theory, activation energy and the Arrhenius equation.
- Surface Chemistry: Learn adsorption, catalysis and enzyme catalysis. Study colloids, their types and properties such as the Tyndall effect, Brownian movement, electrophoresis, coagulation and emulsions.
Inorganic Chemistry
- Hydrogen and s-Block Elements: Study the position, isotopes and compounds of hydrogen, including water, heavy water and hydrogen peroxide. Learn the trends, reactivity and key compounds of Group 1 and 2 elements and their biological importance.
- p-Block Elements: Groups 13 and 14: Study electronic configuration, trends, anomalous behaviour and reactivity of boron and carbon families. Learn boron compounds, aluminium, carbon allotropes and important compounds of silicon.
- p-Block Elements: Groups 15 to 18: Study trends and reactivity of nitrogen, oxygen, halogen and noble gas families. Learn ammonia, nitric acid, oxides, ozone, sulphur compounds, chlorine, hydrochloric acid, interhalogens and oxoacids.
- d- and f-Block Elements: Study transition metal properties such as oxidation states, colour, catalysis, magnetism and alloy formation. Learn K2Cr2O7 and KMnO4, and compare lanthanoids and actinoids including lanthanoid contraction.
- Isolation of Elements: Learn principles of metal extraction: concentration, oxidation, reduction, electrolytic methods and refining. Study the extraction of aluminium, copper, zinc and iron.
- Coordination Compounds: Study ligands, coordination number, colour, magnetism and shapes, and IUPAC naming. Learn Werner's theory, valence bond and crystal field theory, isomerism and applications.
Organic Chemistry
- Basic Principles and Techniques in Organic Chemistry: Learn classification, IUPAC nomenclature, purification methods and analysis of organic compounds. Study inductive and electromeric effects, resonance, hyperconjugation, reactive intermediates and types of organic reactions.
- Aliphatic Hydrocarbons: Study alkanes, alkenes and alkynes: naming, isomerism, preparation and reactions. Include free radical halogenation, Markownikov's addition, the peroxide effect, ozonolysis and electrophilic addition mechanisms.
- Aromatic Hydrocarbons: Learn benzene, resonance and aromaticity. Study electrophilic substitution (nitration, sulphonation, halogenation, Friedel-Crafts), directive influence and carcinogenicity.
- Haloalkanes and Haloarenes: Study the nature of the C-X bond, physical and chemical properties and substitution mechanisms. Learn optical rotation and the uses and environmental effects of common halogen compounds.
- Alcohols, Phenols and Ethers: Learn naming, preparation, properties and uses of alcohols, phenols and ethers. Study identification of alcohol types, dehydration, the acidic nature of phenol and its substitution reactions.
- Aldehydes, Ketones and Carboxylic Acids: Study the carbonyl group, preparation and properties, nucleophilic addition and alpha-hydrogen reactivity. Learn the acidic nature, preparation and properties of carboxylic acids.
- Organic Compounds Containing Nitrogen: Study amines: classification, preparation, properties and identification. Learn cyanides, isocyanides and diazonium salts and their use in synthesis.
- Biomolecules: Study carbohydrates, proteins, vitamins and nucleic acids: classification, structure and functions. Learn about enzymes, protein structure levels and denaturation.
- Polymers: Learn copolymerization and important natural and synthetic polymers such as polythene, nylon, polyesters, bakelite and rubber. Compare biodegradable and non-biodegradable polymers.
Chemistry in Everyday Life and Environment
- Environmental Chemistry: Study air, water and soil pollution, atmospheric chemistry, smog, acid rain and ozone depletion. Learn about the greenhouse effect, global warming and green chemistry.
- Chemistry in Everyday Life: Learn about chemicals in medicines such as analgesics, antiseptics, antibiotics and antacids. Study food preservatives, sweeteners, antioxidants, soaps and detergents.
Rounds and levels
- 2026-27: Practice for INChO 2026-27 (exam date: 30 January 2027).
- Previous-year papers: Past INChO question papers.
More exams on SkillStar
INChO: questions parents ask
- Which classes can prepare for INChO on SkillStar?
- INChO practice on SkillStar is arranged for Grade 10, Grade 11 and Grade 12. Each child sees what's right for their own class.
- What is in the INChO syllabus for 2026-27?
- 30 topics in Physical Chemistry, Inorganic Chemistry, Organic Chemistry and Chemistry in Everyday Life and Environment, laid out subject by subject on this page. On SkillStar your child can tick off each topic as they learn it.
- Are there INChO mock tests on SkillStar?
- Yes, 13 mock tests. Each one is marked the moment your child finishes, with a question-by-question review, and can be taken again as often as they like.
- Can I download INChO papers?
- Yes. The INChO Downloads tab on SkillStar has 38 files for this exam.
- How does my child start INChO practice?
- Sign up free as a parent, add your child with their class, and pick INChO from the exam list. Every new family gets welcome credits, lots of content costs nothing, and anything paid shows its price in credits before you decide.
- Is SkillStar the official INChO website?
- No. SkillStar is an independent practice platform and is not affiliated with, or endorsed by, the organisers of these exams. Exam names belong to their respective owners. Check dates, fees and registration with the INChO organisers.
SkillStar is an independent practice platform and is not affiliated with, or endorsed by, the organisers of these exams. Exam names belong to their respective owners.