Free mockFree all-India mock this Sunday, 6 pm IST

JEE Main · subject

JEE Main Chemistry preparation: physical, organic and inorganic, chapter by chapter

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

  • JEE Main Chemistry has 20 syllabus units across physical, inorganic and organic chemistry, examined through 25 questions worth 100 marks.
  • In our analysis of past papers, organic chemistry as a whole carries 7–9 questions a paper — more than any single physical or inorganic chapter.
  • Inorganic chemistry is the cheapest section to score in, because most questions follow the NCERT text closely.
  • BrainStride is an AI tutor for JEE, NEET and Olympiad preparation that runs a 20-minute diagnostic, maps your weak chapters and writes a daily plan, with every solution checked by teachers.

Which JEE Main Chemistry chapters carry the most questions?

BrainStride analysis of past papers · questions per shift, ranges vary · NTA publishes no chapter weightage

  • p-Block Elements2–3 Q
  • Chemical Bonding and Molecular Structure1–3 Q
  • Chemical Thermodynamics1–2 Q
  • Equilibrium1–2 Q
  • Chemical Kinetics1–2 Q
  • Classification of Elements and Periodicity in Properties1–2 Q
  • d- and f-Block Elements1–2 Q
  • Co-ordination Compounds1–2 Q
  • Some Basic Principles of Organic Chemistry1–2 Q
  • Hydrocarbons1–2 Q

All 20 Chemistry units, ranked by what they cost you

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.

UnitClassQuestions per paperDifficultyThe mistake it catches
Some Basic Concepts in Chemistry110–2 QEasy–moderateLimiting reagent skipped, so the answer follows the reagent that is in excess.
Atomic Structure110–2 QModerateApplying hydrogen-atom energy formulas to multi-electron species.
Chemical Bonding and Molecular Structure111–3 QModerateCounting lone pairs wrongly, so hybridisation and shape both come out wrong.
Chemical Thermodynamics111–2 QModerateSign of ΔH and ΔG swapped between system and surroundings.
Solutions120–2 QModerateVan’t Hoff factor left out for electrolytes in colligative property sums.
Equilibrium111–2 QModerateKp and Kc used interchangeably without the (RT)^Δn conversion.
Redox Reactions and Electrochemistry11–120–2 QModerateNumber of electrons transferred (n) taken wrong in the Nernst equation.
Chemical Kinetics121–2 QModerateAssuming the order of a reaction from its stoichiometry.
Classification of Elements and Periodicity in Properties111–2 QEasy–moderateQuoting a trend without its exception, which is usually what is being asked.
p-Block Elements11–122–3 QModerateAnswering from half-remembered reactions instead of the NCERT line.
d- and f-Block Elements121–2 QModerateColour and magnetic-moment questions answered without counting unpaired electrons.
Co-ordination Compounds121–2 QModerateOxidation state of the metal miscounted, so CFSE and geometry follow it wrong.
Purification and Characterisation of Organic Compounds110–1 QEasyEmpirical formula questions where percentage data is not converted to moles.
Some Basic Principles of Organic Chemistry111–2 QModerate–hardRanking stability by one effect alone when resonance and inductive effects oppose.
Hydrocarbons111–2 QModerateMarkovnikov and anti-Markovnikov products swapped when peroxide is present.
Organic Compounds Containing Halogens120–1 QModerateSN1 and SN2 chosen by the substrate alone, ignoring solvent and nucleophile.
Organic Compounds Containing Oxygen121–2 QModerateNamed reactions recalled by name but not by the conditions that trigger them.
Organic Compounds Containing Nitrogen120–1 QModerateBasicity of amines compared in the gas phase and in water without distinguishing them.
Biomolecules120–2 QEasyAnswering from a coaching sheet instead of the NCERT text the question is lifted from.
Principles Related to Practical Chemistry11–121–2 QEasy–moderateConfusing 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.

Top 5 mistakes in JEE Main Chemistry

Where Chemistry marks leak most often — mostly in the sections students consider safe.

Inorganic answered from a coaching sheet

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.

Mole concept skipped at the first step

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.

Organic stability judged by one effect

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.

Named reactions without conditions

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.

Sign and n errors in thermodynamics and electrochemistry

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.

How should I split time between physical, organic and inorganic chemistry?

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.

Does NCERT alone cover JEE Main Chemistry?

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.

What order should I revise Chemistry in?

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.

How the Chemistry content here is checked

Every solution is reviewed by a subject teacher before it ships, and explanations are audited weekly. The teachers are on staff, so we describe the process rather than publish a roster.

Read the editorial policy
  • Owns the Chemistry solution bank
  • Organic reasoning and named reactions
  • Weightage ranges are our own reading of past papers — NTA publishes none.
  • Report anything that looks wrong and it is fixed or explained within 48 hours.

JEE Main Chemistry questions students ask

Anything missing? Write to hello@brainstride.co — a mentor replies, not a bot.

Which chapters are most important for JEE Main Chemistry?

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.

How many questions come from organic chemistry in JEE Main?

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.

Is NCERT enough for JEE Main Chemistry?

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.

Which is the easiest section in JEE Main Chemistry?

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.

How do I improve accuracy in physical chemistry numericals?

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.

Should I study Chemistry chapters in NCERT order?

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.

Official sources

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.

Which Chemistry chapters are quietly costing you marks?

A 20-minute diagnostic names them, then writes the plan that closes them. Free, no card.