Top 10 Most Repeated Topics In Chemistry For JEE Mains 2026 - High Scoring Areas to Crack IIT JEE

Most Repeated Chemistry Topics For JEE Mains 2026

Preparing for any exam requires research and specially for a competitive entrance exam like JEE Mains requires thorough preparation. So, our experts have collected and done the thorough research for you already. In the below table we have provided you with the top 10 most repeated topics in chemistry for JEE Mains 2026. This data comprises last 10 years JEE mains question papers of all slots.

This table contains the most repeated chemistry topics for JEE Mains. For more details we have also provided you with a count of the total numbers of questions from these topics (from last 10 years data) along with the chapters that they are from.

As seen, the topic Concentration Terms happen to be the most important with the highest weighted topic. The 10th most important topic is Oxidation State, a part of both the chapters : d-Block Element and Redox Reactions. Following this list, we have more high weighted topics which could be a game changer for the JEE mains chemistry exam: Depression in Freezing Point, Kmno4 - Potassium Permanganate and Reaction with NaNO₂ + HCl. These 3 topics also have a high frequency of questions asked in the last 10 years but couldn't make it to the top 10 most repeated topics in chemistry for jee mains. However, they can’t be ignored!

Now, after seeing the topics, let’s dive into the most important chapters for JEE mains chemistry 2026. Understanding this aspect will give you an upper hand in the preparation for the exam!

JEE Main- Top 30 Most Repeated Questions & Topics

Top 10 Most Important Chapters For JEE Mains Chemistry 2026

We have already seen the most repeated chemistry topics for jee mains and the chapters that they are asked from. Now, let’s see which chapters have the highest number of questions from the past 10 years. Most important chapters for JEE mains Chemistry 2026 are curated by analyzing the frequency of the questions asked from the whole chapter in the last 10 years.

This table contains the chapter name on one side and the total number of questions asked from each chapter on the other side. These following listed chapters constitute the most important chapters for JEE mains chemistry 2026 with organic compounds containing oxygen being the highest weighted chapter. This list has 17 most important chapters ranked in order of most to least important.

Chemical kinetics happens to be the last chapter having more than 100 questions asked in the last 10 years. After this we have 99 questions asked from Purification and Characterisation of Organic Compounds and 94 asked from Environmental Chemistry. Please note that all the chapters are important and need to be studied thoroughly before the exam. We have given the list of the most repeated chemistry topics for JEE Mains so that you know where to start and which chapters to give the most importance to.

Most Repeated Questions in JEE Mains Chemistry 2026

In this section, we will be diving into each topic and looking at the set of most important questions from those particular topics listed above individually. Understanding the level of these questions and practicing them will help you increase your chances of scoring better and increasing your rank in JEE Mains exam 2026. Let’s dive in!

1. Concentration Terms

Q.1) Concentrated nitric acid is labelled as $75\mathrm{\%}$ by mass. The volume in mL of the solution which contains 30 g of nitric acid is _________. Given : Density of nitric acid solution is $1.25\mathrm{g}/\mathrm{mL}$

A) 45

B) 55

C) 32

D) 32

Solution:-

$75\mathrm{\%}$ by mass means :

$\because 75\mathrm{g}{\mathrm{HNO}}_3$ in 100 g solution.

$\therefore 30\mathrm{g}{\mathrm{HNO}}_3$ in $\frac{100}{75}\times 30\mathrm{g}$ solution.

${\mathrm{m}}_{\text{solution}}=\frac{100\times 30}{75}\mathrm{g}$

$\because {\mathrm{V}}_{\text{sol}}=\frac{{\mathrm{m}}_{\text{sol}}}{{\mathrm{d}}_{\text{sol}}}=\frac{100\times 30}{75\times 1.25}=32\mathrm{mL}$

Hence, the correct answer is option (3).

2. Mole Concept And Molar Mass

Question: The percentage composition of carbon by 1 mole in methane is:

1. 75

2. 80

3. 25

4. 20 (correct)

Number of Moles -

No of moles = given mass of substance/ molar mass of substance

$$\begin{array}{rl}\text{mole}\mathrm{\%}\text{of '}{\mathrm{C}}^{\prime }\text{in}{\mathrm{CH}}_4& =\frac{\text{mole of}C}{\text{mole of}C+\text{mole of hydrogen}}\times 100\\ =\frac{n_c}{n_H+n_c}\times 100\end{array}$$

For 1 mole of C , there are 4 moles of hydrogen

$$\begin{array}{r}\therefore n_c=1\text{and}{n}_H=4\\ =\frac{1}{1+4}\times 100=20\mathrm{\%}\end{array}$$

Hence, the answer is $(20\mathrm{\%})$.

3. Magnetic Moment (on the basis of VBT)

Question:
The calculated spin-only magnetic moments of … and … respectively are:

Options:

1. 4.90 and 4.90 B.M.

2. 5.92 and 4.90 B.M. (correct)

3. 3.87 and 4.90 B.M.

4. 4.90 and 5.92 B.M.

Answer:
The spin-only magnetic moment is given by:

μ=n(n+2)

where n = number of unpaired electrons.

• For the first complex, oxidation state of Fe is +3, configuration = 3d⁵.
  With weak field ligands → high-spin → 5 unpaired electrons.
  Magnetic moment = √(5(5+2)) = √35 = 5.92 B.M.

• For the second complex, oxidation state of Fe is +2, configuration = 3d⁶.
  With weak field ligands → high-spin → 4 unpaired electrons.
  Magnetic moment = √(4(4+2)) = √24 = 4.90 B.M.

Hence, the spin-only magnetic moments are 5.92 B.M. and 4.90 B.M. → Option (2).

4. Stoichiometry, Stoichiometric Calculations and Limiting Reagent

Question:
For per gram of reactant taken, the maximum quantity of N₂ gas is produced in which of the following thermal decomposition reactions?
(Given: Atomic wt. Cr = 52 u, Ba = 137 u)

Options:

1. $(\mathrm{NH}4)2\mathrm{Cr}2\mathrm{O}7(\mathrm{s})\to \mathrm{N}2(\mathrm{g})+4\mathrm{H}2\mathrm{O}(\mathrm{g})$

2. $2\mathrm{NH}4\mathrm{NO}3(\mathrm{s})\to 2\mathrm{N}2(\mathrm{g})+4\mathrm{H}2\mathrm{O}(\mathrm{g})+\mathrm{O}2(\mathrm{g})$

3. $\mathrm{Ba}(\mathrm{N}3)2(\mathrm{s})\to \mathrm{Ba}(\mathrm{s})+3\mathrm{N}2(\mathrm{g})$

4. $2\mathrm{NH}3(\mathrm{g})\to \mathrm{N}2(\mathrm{g})+3\mathrm{H}2(\mathrm{g})$ (correct)

Answer:

- (NH₄)₂Cr₂O₇: Molar mass =252 g; produces 28 g N ₂ .

$\to 1\mathrm{g}$ gives $28/252=0.11\mathrm{g}\mathrm{N}2$.

- NH4NO3 : Molar mass $=80\mathrm{g}$; from 160 g gives 56 g N 2 .

$\to 1\mathrm{g}$ gives $56/160=0.35\mathrm{g}\mathrm{N}2$.

- $\mathrm{Ba}(\mathrm{N}3)2$ : Molar mass $=440\mathrm{g}$; gives 84 g N 2 .

$\to 1\mathrm{g}$ gives $84/440=0.19\mathrm{g}\mathrm{N}2$.

- NH3 : Molar mass = 17 g ; from 34 g gives 28 g N 2 .

$\to 1\mathrm{g}$ gives $28/34=0.83\mathrm{g}\mathrm{N}2$.

Thus, the maximum N₂ per gram of reactant is obtained from NH₃ decomposition, i.e., Option (4).

5. Applications of CFT

Question:
Match List I with List II

Choose the correct answer from the options given below:

1. A–II, B–III, C–IV, D–I

2. A–II, B–IV, C–I, D–III

3. A–III, B–IV, C–II, D–I

4. A–II, B–III, C–I, D–IV (correct)

Answer:

• Mg(NH₄)PO₄ → White

• K₃[Co(NO₂)₆] → Yellow

• MnO(OH)₂ → Brown

• Fe₄[Fe(CN)₆]₃ → Blue

Explanation:

• Colour in coordination compounds arises from d-d transitions explained by crystal field theory.

• Weak field ligands lead to low splitting energy; strong field ligands lead to high splitting energy.

• The complementary colour of absorbed light determines the observed colour.

Hence, the correct matching is A–II, B–III, C–I, D–IV (Option 4).

6. Stereoisomerism

Question:
"P" is an optically active compound with molecular formula … . When "P" is treated with 2,4-dinitrophenylhydrazine, it gives a positive test. However, in presence of Tollens’ reagent, "P" gives a negative test. Predict the structure of "P".

Solution

P gives a negative test with Tollen’s reagent, so it is not an aldehyde.
Also, P is optically active, so the compound will be the one given in option 2 (C-3 is chiral carbon)

Hence, the correct answer is option (2).

7. Stereoisomerism

Question:

The number of optical isomers exhibited by the iron complex (A) obtained from the following reaction is______

${\mathrm{FeCl}}_3+\mathrm{KOH}+{\mathrm{H}}_2{\mathrm{C}}_2{\mathrm{O}}_4\to A$

Solution:

1. The compound dissociates.

2. It ionises in solution under the influence of KOH.

3. KOH neutralises the acidic medium.

4. It reacts with 3 oxalate ions to form the complex.

Here, the resulting compound is the potassium salt of the complex anion and is an octahedral type complex.

Number of total optical isomers = 2ⁿ, where n is the number of chiral centers.
The chiral center in the given compound is 1.
Total optical isomers = 2¹ = 2.

8. Disaccharides – Carbohydrate Linkages

Question: Match List - I with List - II.

Polysaccharides are carbohydrates composed of hundreds or thousands of monosaccharide units joined by glycosidic linkages. The type of glycosidic bond determines structure and function.

• Amylose: Found in plants, unbranched starch, α-(C₁ → C₄) glycosidic bonds.

• Cellulose: Found in plants (structural component), β-(C₁ → C₄) glycosidic bonds.

• Glycogen: Found in animals (energy storage), branched, α-(C₁ → C₄) and α-(C₁ → C₆) glycosidic bonds.

• Amylopectin: Found in plants, branched starch, α-(C₁ → C₄) and α-(C₁ → C₆) glycosidic bonds.

9. First Order Reaction

Question:

An organic compound undergoes first order decomposition. If the time taken for the 60% decomposition is 540 s, then the time required for 90% decomposition will be is______ s. (Nearest integer).

Given: ln 10 = 2.3; log 2 = 0.3

$\begin{array}{rl}\mathrm{K}& =\frac{2.303}{540}\log \frac{100}{40}\\ \mathrm{K}& =\frac{2.303}{540}\times 0.4\\ {\mathrm{t}}_{90}& =\frac{2.303\times 540}{2.303\times 0.4}\log \frac{100}{10}\\ {\mathrm{t}}_{90}& =1350\end{array}$

Hence, the answer is (1350).

10. Oxidation State

Question: Consider the following two statements:

• Statement I: Cr(VI) is a stronger oxidizing agent than Mo(VI).

• Statement II: Cr(VI) is more stable than Mo(VI).

In light of the above statements, choose the correct answer from the options given below:

1. Statement I is false but Statement II is true

2. Statement I is true but Statement II is false (Correct)

3. Both Statement I and Statement II are true

4. Both Statement I and Statement II are false

Solution:

• Statement I is true:
  Cr(VI), especially in the form of dichromate Cr₂O₇^2- in acidic medium, acts as a strong oxidizing agent. It readily gets reduced to Cr(III), making it highly reactive in redox reactions. In contrast, Mo(VI) (as in MoO₃) and W(VI) (as in WO₃) are more stable and do not exhibit strong oxidizing behavior.

• Statement II is false:
  Cr(VI) is less stable than Mo(VI). Molybdenum and tungsten, being heavier congeners in Group 6, form more stable +6 oxidation state compounds compared to chromium.

Conclusion:
Cr(VI) is a stronger oxidizing agent but less stable than Mo(VI).
Correct answer: Option 2 — Statement I is true but Statement II is false.

Most Repeated Chemistry Topics For JEE Mains

Now that we have seen the most important chapters for JEE mains chemistry 2026, lets dive into each section of chemistry part by part.

In JEE Mains, chemistry is divided into 3 parts. A brief of each part is given below:

1. Physical chemistry - conceptual and numerical understanding of chemistry.

2. Organic Chemistry - high reaction mechanisms, named reactions, functional groups.

3. Inorganic Chemistry - diving into periodic table, fact based studies, nature of elements and compounds.

Studying smart is as important as studying hard. It is always better to know the subject and prioritize some topics and chapters to be able to ace the exam. Therefore, the following data is categorized according to each of the sections where we have given the most important chapters and most repeated questions for your preparation.

This table gives you a smooth understanding of where to focus and what to begin with in each section. Now, lets see the most important chapters for JEE Mains chemistry 2026 for physical chemistry, followed by organic and inorganic chemistry.

Physical Chemistry Most important chapters for JEE mains Chemistry 2026

The chapters with highest weightage are given in the table below:

Organic Chemistry Most important chapters for JEE mains Chemistry 2026

Inorganic Chemistry Most important chapters for JEE mains Chemistry 2026

Best Books for Top 10 Most Repeated Topics in Chemistry

We have seen every possible classification of important chapters and topics for Chemistry 2026. Our experts have also listed down the main books to be referred for the preparation of those exclusive topics. You can certainly use these books to prepare for other topics as well.

These are the top most important topics topics and chapters for JEE mains 2026 along with the best preferable book for their preparation.