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Many students who enjoy chemistry hear about the olympiad only after the enrolment window has closed. Others sit the first paper expecting a harder board exam and find something closer to a puzzle. This post explains each stage of the chemistry olympiad in India, how students move between them, what the papers look like and how to start preparing.
How does the chemistry olympiad work in India?
HBCSE, a national centre of the Tata Institute of Fundamental Research, runs the science olympiads. Its stages page describes five stages. The first, the National Standard Examination in Chemistry (NSEC), is organised by the Indian Association of Physics Teachers, with academic responsibility for chemistry resting with the Association of Chemistry Teachers. HBCSE runs everything after that. The page says the first two stages do not necessarily require specialised coaching outside school, and that the ₹300 registration fee is the only fee a student pays in the whole process.
NSEC, the first stage.
INChO, the Indian National Chemistry Olympiad, for about 400 students.
Orientation-cum-selection camp at HBCSE for about 40 students, with theory and experimental tests.
Training for the selected team.
The International Chemistry Olympiad (IChO).
What does the NSEC paper look like?
The HBCSE Science Olympiad brochure for 2026-27 gives the pattern. NSEC 2026 is on 22 November 2026, from 11:30 to 13:30. It has two parts:
Part A: 48 multiple-choice questions with one correct option, +3 for a correct choice and −1 for a wrong one.
Part B: 12 questions of six marks each with one or more correct options. To get credit, you must mark all the correct options and no incorrect ones.
The syllabus is broadly equivalent to CBSE senior secondary level, up to and including Class 12. The brochure also gives the eligibility rules, including a date of birth between 1 July 2007 and 30 June 2012 and studying in Class 10, 11 or 12 at enrolment. Enrolment for 2026 ran from 21 August to 14 September 2026 through schools or the IAPT website, so if you missed it, plan for the next cycle and check the dates when they are announced.
How do students qualify for INChO?
The brochure sets a Minimum Admissible Score (MAS) of 50% of the average of the top ten NSEC scores, rounded down. Its own example: if the top ten average 92.3, the MAS is 46. Anyone scoring at least the Merit Index, 80% of that average (73 in the same example), qualifies automatically. Beyond that, a state-wise quota applies, and the target is 200 students from Class 12 and 200 from Classes 10 and 11. A supernumerary quota aims to ensure that at least 20% of those selected are female, subject to the MAS.
INChO 2027 is on 30 January 2027, from 13:30 to 16:30. HBCSE's past papers page has INChO papers with model solutions. The INChO 2025 theory paper was a three-hour paper worth 109 marks, built from five long problems. The first, "The golden alloy", starts from a short account of when metals form alloys and then asks a chain of questions.
According to the brochure, the camp selects a four-student team, and the 59th IChO is planned for Chinese Taipei in July 2027.
What kind of chemistry does the olympiad test?
The concepts are in your NCERT books, but questions combine them and give you data to interpret. Here is a problem of the kind you will meet.
Worked example. A 0.92 g mixture of calcium carbonate and magnesium carbonate is heated until both decompose completely, giving 0.44 g of carbon dioxide. Find the mass of each carbonate. (Use CaCO₃ = 100, MgCO₃ = 84, CO₂ = 44 g/mol.)
Each carbonate gives one CO₂ per formula unit: MCO₃ → MO + CO₂.
Moles of CO₂ = 0.44/44 = 0.010 mol.
Let x g be CaCO₃. Then MgCO₃ is (0.92 − x) g.
Moles of carbonate = moles of CO₂: x/100 + (0.92 − x)/84 = 0.010.
Multiply through by 8400: 84x + 100(0.92 − x) = 84, so 92 − 16x = 84, and x = 0.50 g.
CaCO₃ = 0.50 g and MgCO₃ = 0.42 g.
Check: 0.50/100 + 0.42/84 = 0.005 + 0.005 = 0.010 mol. Correct.
The common mistake is assuming the two carbonates are present in equal masses, or forgetting that each mole of carbonate gives one mole of CO₂.
How should you start preparing?
Finish the NCERT basics first. Get the mole concept, equilibrium, thermodynamics, bonding and organic mechanisms solid before anything else. Our guide to organic mechanisms explains why understanding beats memorising lists.
One INChO problem a week. Give it a full hour before reading the model solution, then redo it two days later.
Practise NSEC-style objective sets. Time yourself on sets of 12, and for multi-correct questions, mark only when you are sure of the whole set.
Write every step. Long INChO problems reward clear working.
Talk to your school. Ask whether it is a registered NSE centre for next year.
When a model solution uses an idea you have not met, such as a crystal structure or a rate law, the Fermi Concept Library covers every concept in physics, chemistry, biology, mathematics and computing, each with its own lesson. For the physics olympiad, which follows the same stages, read our post on getting started with the physics olympiad.
This week, download the INChO 2025 paper and attempt Problem 1 before you look at the model solution.
