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CBSE Class 11 Important Question for Chemistry
By Swati Singh
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Updated on 14 Jul 2025, 15:20 IST
CBSE Class 11 Maths Important Questions play a vital role in a student’s preparation, especially as the subject becomes significantly more challenging at this level. This resource offers insight into the variety of question types that may appear in the examination. Students can explore chapter-wise sets of important questions curated in our question bank to deepen their understanding and strengthen conceptual clarity. Many of these questions are likely to be asked in upcoming exams. Consistent daily practice will help students build confidence and perform exceptionally well.
CBSE Class 11 Important Questions Chemistry - Chapter wise
| Chapter No. | Chapter Name | Focus Areas for Important Questions |
| 1 | Some Basic Concepts of Chemistry | Mole concept, Stoichiometry, Limiting reagent |
| 2 | Structure of Atom | Atomic models, Quantum numbers, Electronic configuration |
| 3 | Classification of Elements & Periodicity | Mendeleev’s table, Modern periodic law, Periodic trends |
| 4 | Chemical Bonding and Molecular Structure | Types of bonds, VSEPR theory, Hybridization, Bond parameters |
| 5 | States of Matter | Gas laws, Ideal gas equation, Kinetic theory of gases |
| 6 | Thermodynamics | First law, Enthalpy, Heat capacity, Hess’s Law |
| 7 | Equilibrium | Equilibrium constant, Le Chatelier’s Principle, pH concepts |
| 8 | Redox Reactions | Oxidation number, Balancing equations, Redox titrations |
| 9 | Hydrogen | Properties, Hydrides, Hydrogen as fuel |
| 10 | The s-Block Element | Alkali & alkaline earth metals, Anomalous behavior of Li, Be |
| 11 | The p-Block Element | Group 13 and 14 elements, Important compounds |
| 12 | Organic Chemistry: Some Basic Principles | IUPAC nomenclature, Reaction types, Electron displacement |
| 13 | Hydrocarbons | Alkanes, Alkenes, Alkynes, Aromatic hydrocarbons |
| 14 | Environmental Chemistry | Air pollution, Water pollution, Green chemistry concepts |
Class 11 Chemistry Important Questions with Solutions
1. Define mole. How many atoms are there in 1 mole of oxygen gas?
Solution: A mole is the amount of a substance containing 6.022 × 10²³ elementary entities (Avogadro's number). In 1 mole of oxygen gas (O₂), there are 6.022 × 10²³ molecules or 1.2044 × 10²⁴ atoms.
2. State Hund’s Rule.
Solution: Hund’s Rule states that electrons occupy degenerate orbitals singly first with parallel spins to minimize electron repulsion and maximize stability.
3. What is periodicity in properties of elements?
Solution: Periodicity is the repetition of similar physical and chemical properties at regular intervals in the periodic table due to recurring electronic configurations.
4. What type of bond exists in NaCl?
Solution: NaCl contains an ionic bond, formed by the transfer of an electron from sodium to chlorine.
5. State Boyle’s law.
Solution: Boyle’s law states that at constant temperature, the pressure of a fixed mass of gas is inversely proportional to its volume.
6. Write the First Law of Thermodynamics.
Solution: Energy can neither be created nor destroyed. Mathematically, ΔU = q + w where ΔU = change in internal energy, q = heat, w = work done.
7. Give two examples of reversible reactions.
Solution:
- N₂ + 3H₂ ⇌ 2NH₃
- 2SO₂ + O₂ ⇌ 2SO₃
8. What is the oxidation number of Cr in K₂Cr₂O₇?
Solution: The oxidation number of Cr is +6.
9. What is hydrogen bond? Give one example.
Solution: A hydrogen bond is a weak attraction between hydrogen atom and electronegative atoms like O, N, or F. Example: H₂O forms hydrogen bonds.
10. Name the strongest reducing agent among alkali metals.
Solution: Lithium (Li) is the strongest reducing agent among alkali metals.
11. Which element is a metalloid: Si, Na, O, Cl?
Solution: Silicon (Si) is a metalloid.
12. What is IUPAC name of CH₃CH₂CH₂CH₃?
Solution: The IUPAC name is Butane.
13. Define hybridisation.
Solution: Hybridisation is the mixing of atomic orbitals to form equivalent hybrid orbitals of equal energy.
14. State Avogadro’s Law.
Solution: Equal volumes of gases at the same temperature and pressure contain equal number of molecules.
15. What is enthalpy (H)?
Solution: Enthalpy is the total heat content of a system, given by H = U + PV.
16. Why is water a universal solvent?
Solution: Water is called a universal solvent because it dissolves more substances than any other liquid due to its polarity and hydrogen bonding ability.
17. Define pH.
Solution: pH = -log[H⁺]; it measures the acidity or basicity of a solution.
18. Name one compound each for ionic and covalent bonds.
Solution:
- Ionic: NaCl
- Covalent: CH₄
19. Explain the octet rule.
Solution: The octet rule states that atoms tend to have eight electrons in their outermost shell for stability.
20. What is resonance?
Solution: Resonance refers to delocalization of electrons in molecules represented by two or more valid Lewis structures. Example: Benzene.
21. Give an example of amphoteric oxide.
Solution: Zinc oxide (ZnO) is amphoteric as it reacts with both acids and bases.
22. What is meant by ionisation enthalpy?
Solution: Ionisation enthalpy is the energy required to remove an electron from a gaseous atom to form a cation.
23. Which compound is used to remove hardness of water?
Solution: Washing soda (Na₂CO₃) is used to remove hardness of water.
24. Name the shape of methane molecule.
Solution: Methane (CH₄) has a tetrahedral shape.
25. What is allotropy? Give one example.
Solution: Allotropy is the existence of an element in more than one physical form. Example: Carbon as diamond and graphite.
FAQs on CBSE Class 11 Important Question for Chemistry
Why are Class 11 Chemistry Important Questions essential for exam preparation?
Class 11 Chemistry Important Questions help students understand the key concepts, practice frequently asked problems, and improve their problem-solving speed. These questions are selected from crucial topics that have a higher probability of being asked in school exams, periodic assessments, and competitive entrance tests like NEET and JEE.
How are important questions for Class 11 Chemistry selected?
Important questions are selected by subject experts after analyzing previous years' papers, CBSE sample papers, and the weightage of chapters. Priority is given to questions that test conceptual clarity, numerical application, and reasoning ability.
Which chapters of Class 11 Chemistry have the highest weightage in exams?
Chapters like Some Basic Concepts of Chemistry, Structure of Atom, Chemical Bonding and Molecular Structure, Thermodynamics, Equilibrium, and Organic Chemistry: Some Basic Principles usually carry more weightage in Class 11 Chemistry exams. These chapters are also foundational for Class 12 and entrance exams.
Can practicing important questions improve my score in Class 11 Chemistry?
Yes, practicing chapter-wise important questions enhances your conceptual understanding, helps in quick revisions, and boosts confidence before exams. It also improves your ability to handle tricky or application-based questions.
Are the Class 11 Chemistry Important Questions based on the latest CBSE syllabus?
Absolutely, the important questions are always aligned with the latest CBSE syllabus and NCERT textbook guidelines. This ensures students practice relevant and updated content as per the academic session.
Do CBSE board exams for Class 11 Chemistry directly ask these important questions?
While exact questions may vary, many questions in school exams are similar to these important questions, either in concept or numerical pattern. Practicing them increases your chance of scoring well in term exams, unit tests, and pre-boards.
Do important questions cover both numerical and theory parts of Chemistry?
Yes, Class 11 Chemistry Important Questions include a balanced mix of numericals, derivations, theoretical concepts, definitions, and application-based questions to ensure comprehensive coverage of all sections.