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JEE Main · subject
Chemistry carries 25 of the 75 questions in JEE Main and 100 of the 300 marks, split across 20 syllabus units. This page ranks every unit by how often past papers draw on it, separates the chapters that reward NCERT recall from the ones that need practice, and names the mistake each unit catches.
Quick answer
BrainStride analysis of past papers · questions per shift, ranges vary · NTA publishes no chapter weightage
Unit names follow the official JEE Main syllabus, grouped as physical, inorganic and organic chemistry. The ranges are ours, from past papers; the mistake column is the error each unit catches most often.
| Unit | Class | Questions per paper | Difficulty | The mistake it catches |
|---|---|---|---|---|
| Some Basic Concepts in Chemistry | 11 | 0–2 Q | Easy–moderate | Limiting reagent skipped, so the answer follows the reagent that is in excess. |
| Atomic Structure | 11 | 0–2 Q | Moderate | Applying hydrogen-atom energy formulas to multi-electron species. |
| Chemical Bonding and Molecular Structure | 11 | 1–3 Q | Moderate | Counting lone pairs wrongly, so hybridisation and shape both come out wrong. |
| Chemical Thermodynamics | 11 | 1–2 Q | Moderate | Sign of ΔH and ΔG swapped between system and surroundings. |
| Solutions | 12 | 0–2 Q | Moderate | Van’t Hoff factor left out for electrolytes in colligative property sums. |
| Equilibrium | 11 | 1–2 Q | Moderate | Kp and Kc used interchangeably without the (RT)^Δn conversion. |
| Redox Reactions and Electrochemistry | 11–12 | 0–2 Q | Moderate | Number of electrons transferred (n) taken wrong in the Nernst equation. |
| Chemical Kinetics | 12 | 1–2 Q | Moderate | Assuming the order of a reaction from its stoichiometry. |
| Classification of Elements and Periodicity in Properties | 11 | 1–2 Q | Easy–moderate | Quoting a trend without its exception, which is usually what is being asked. |
| p-Block Elements | 11–12 | 2–3 Q | Moderate | Answering from half-remembered reactions instead of the NCERT line. |
| d- and f-Block Elements | 12 | 1–2 Q | Moderate | Colour and magnetic-moment questions answered without counting unpaired electrons. |
| Co-ordination Compounds | 12 | 1–2 Q | Moderate | Oxidation state of the metal miscounted, so CFSE and geometry follow it wrong. |
| Purification and Characterisation of Organic Compounds | 11 | 0–1 Q | Easy | Empirical formula questions where percentage data is not converted to moles. |
| Some Basic Principles of Organic Chemistry | 11 | 1–2 Q | Moderate–hard | Ranking stability by one effect alone when resonance and inductive effects oppose. |
| Hydrocarbons | 11 | 1–2 Q | Moderate | Markovnikov and anti-Markovnikov products swapped when peroxide is present. |
| Organic Compounds Containing Halogens | 12 | 0–1 Q | Moderate | SN1 and SN2 chosen by the substrate alone, ignoring solvent and nucleophile. |
| Organic Compounds Containing Oxygen | 12 | 1–2 Q | Moderate | Named reactions recalled by name but not by the conditions that trigger them. |
| Organic Compounds Containing Nitrogen | 12 | 0–1 Q | Moderate | Basicity of amines compared in the gas phase and in water without distinguishing them. |
| Biomolecules | 12 | 0–2 Q | Easy | Answering from a coaching sheet instead of the NCERT text the question is lifted from. |
| Principles Related to Practical Chemistry | 11–12 | 1–2 Q | Easy–moderate | Confusing the confirmatory tests for two ions of the same group. |
Ranges are per shift and overlap — a single paper has 25 Chemistry questions, so no shift draws on every unit.
Where Chemistry marks leak most often — mostly in the sections students consider safe.
Why it happens
The question is lifted from an NCERT line that the summary sheet compressed or left out.The fix
Read the NCERT paragraph for every p-block and d-block reaction once, and keep the sheet for revision only.Why it happens
Percentage or mass data is used directly, without converting to moles or finding the limiting reagent.The fix
Convert to moles in line one of every stoichiometry question, before anything else.Why it happens
Resonance, inductive and hyperconjugative effects pull in different directions, and only one is considered.The fix
List the competing effects, then rank them — a written comparison beats an instinct in a timed paper.Why it happens
The name is recalled but the reagent, solvent or temperature that decides the product is not.The fix
Learn each named reaction as a triple: substrate, condition, product. Drill the condition, not the name.Why it happens
ΔH and ΔG signs flip between system and surroundings, and n in the Nernst equation is taken from the formula rather than the half-reaction.The fix
Write the balanced half-reactions first; read n and the sign convention off them.The 20 units grouped the way students study them. Ranges are the sum of the unit ranges above; shares use the midpoints, so they add to 100% while the ranges overlap.
| Branch | Units | Questions per paper | Share of the section | Marks at stake |
|---|---|---|---|---|
| Physical chemistry | 8 | 4–17 | 40% | 16–68 |
| Inorganic chemistry | 4 | 5–9 | 27% | 20–36 |
| Organic chemistry | 7 | 3–11 | 27% | 12–44 |
| Practical chemistry | 1 | 1–2 | 6% | 4–8 |
BrainStride analysis of past papers · questions per shift, ranges vary · NTA publishes no chapter weightage
Physical chemistry — Some Basic Concepts in Chemistry, Atomic Structure, Chemical Bonding and Molecular Structure, Chemical Thermodynamics, Solutions, Equilibrium, Redox Reactions and Electrochemistry, Chemical Kinetics — brings about 4–17 of the 25 Chemistry questions a shift in our reading of past papers, roughly 40% of the section, or 16–68 marks. The heaviest units inside it are Chemical Bonding and Molecular Structure (1–3) and Chemical Thermodynamics (1–2).
Inorganic chemistry — Classification of Elements and Periodicity in Properties, p-Block Elements, d- and f-Block Elements, Co-ordination Compounds — brings about 5–9 of the 25 Chemistry questions a shift in our reading of past papers, roughly 27% of the section, or 20–36 marks. The heaviest units inside it are p-Block Elements (2–3) and Classification of Elements and Periodicity in Properties (1–2).
Organic chemistry — Purification and Characterisation of Organic Compounds, Some Basic Principles of Organic Chemistry, Hydrocarbons, Organic Compounds Containing Halogens, Organic Compounds Containing Oxygen, Organic Compounds Containing Nitrogen, Biomolecules — brings about 3–11 of the 25 Chemistry questions a shift in our reading of past papers, roughly 27% of the section, or 12–44 marks. The heaviest units inside it are Some Basic Principles of Organic Chemistry (1–2) and Hydrocarbons (1–2).
Practical chemistry brings about 1–2 of the 25 Chemistry questions a shift in our reading of past papers, roughly 6% of the section, or 4–8 marks.
Not equally. In our reading of past JEE Main papers, organic chemistry carries 7–9 questions, physical around ten and inorganic the rest — but the time each needs is the other way round. Inorganic is the cheapest: most of it is NCERT recall, and a disciplined reading pass plus regular revision converts directly into marks. Organic needs daily practice because it is reasoning, not recall. Physical sits in between and is the section where silly errors cost the most.
For inorganic chemistry, close to it — the questions follow the book, including lines that summary sheets tend to drop. For physical chemistry NCERT gives the theory but not enough numerical practice, and for organic it gives the reactions but not the multi-step reasoning a paper asks for. The honest answer: NCERT is necessary and sufficient for inorganic, necessary but not sufficient for the other two.
Revise inorganic last and most often — it fades fastest. Organic needs to be kept warm with a few questions every day rather than revisited in blocks. Physical behaves like Physics: the method survives if you have solved enough problems. BrainStride’s spaced revision schedules the fade for you, resurfacing a cleared chapter the week before you would have forgotten it. Track what is finished in the syllabus tracker.
The order above is a Chemistry-only view. The chapter-wise weightage analysis puts the Chemistry units next to Physics and Maths so you can see which subject repays the next hour, and the JEE Main hub keeps the pattern, syllabus and dates together. Electrochemistry and thermodynamics are the two physical-chemistry chapters most students lose marks in, and each has a guide with the formulas and the sign conventions that go wrong. After the exam, the answer key page explains how to score your response sheet, and the cutoff page shows the percentile that qualified for JEE Advanced each year. If Advanced is the goal, note that several chapters cut from JEE Main in 2024 are still on the JEE Advanced syllabus.
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In BrainStride’s analysis of past JEE Main papers, organic chemistry as a whole carries 7–9 of the 25 Chemistry questions, with p-Block Elements (2–3), Chemical Bonding (1–3) and Coordination Compounds (1–2) the heaviest single units. NTA publishes no official weightage, so these are ranges from past papers rather than a promise for 2027.
Organic chemistry accounts for about seven to nine of the 25 JEE Main Chemistry questions in our reading of recent papers, spread across general organic principles, hydrocarbons, oxygen- and nitrogen-containing compounds, biomolecules and practical chemistry. That makes it the largest block in the paper, and the one that needs daily practice rather than revision in blocks.
NCERT is close to sufficient for inorganic chemistry, where JEE Main questions follow the text closely, including details that summary sheets drop. For physical chemistry it gives the theory but too few numericals, and for organic chemistry it gives the reactions without the multi-step reasoning papers ask for. Use NCERT as the base and practise beyond it for those two.
Inorganic chemistry is usually the cheapest section to score in, because most questions test whether you have read the NCERT text rather than whether you can solve a problem. It also fades fastest from memory, so it needs frequent short revision rather than one long study block early in the year.
Physical chemistry errors cluster in a few places: moles not taken at the first step, the van’t Hoff factor omitted for electrolytes, and n in the Nernst equation read from the formula rather than the half-reaction. Practise those specific steps rather than whole chapters — BrainStride tags each wrong answer so the next set targets the step you missed.
Not strictly. Follow your school and coaching sequence for physical and organic chemistry so class work reinforces practice, but read inorganic chapters as soon as the corresponding NCERT chapter is done, then keep revisiting them. Inorganic rewards repetition more than sequence, which is why spaced revision matters most there.
BrainStride is not affiliated with NTA. Chapter weightage is our own analysis of past papers — NTA publishes none. Confirm the syllabus and pattern against the current official bulletin.
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