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Some Basic Concepts of Chemistry CBSE Class 11 MCQ & Practice Questions

Practice Some Basic Concepts of Chemistry MCQs for CBSE Class 11 Chemistry with answers, explanations, chapter revision and related ChemNexa mock tests.

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Some Basic Concepts of Chemistry Revision Guide for CBSE Class 11 Chemistry

Some Basic Concepts of Chemistry is part of CBSE Class 11 Chemistry preparation. A strong revision plan should combine concept review with exam-style questions so that definitions, relationships, calculations and exceptions are recalled accurately.

Use the sample MCQs on this page to check understanding, then attempt the related ChemNexa tests for broader practice. When an answer is wrong, review the explanation and return to the underlying concept before attempting another set.

Important Topics

  • Core definitions and principles
  • Important equations or relationships
  • Common applications and examples
  • Frequently confused concepts
  • Exam-style multiple-choice questions
  • Error review and targeted revision

Revision Tip

Create a one-page summary of trends, structures, reactions, exceptions and key terminology for Some Basic Concepts of Chemistry, then test recall with mixed MCQs.

What to practise in Some Basic Concepts of Chemistry

Concept Revision

Revise definitions, principles, equations, trends and core ideas from Some Basic Concepts of Chemistry before attempting MCQs.

Exam-style MCQs

Use chapter-focused multiple-choice practice to improve accuracy, recall and application for CBSE Class 11 Chemistry.

Performance Practice

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Top 20 Some Basic Concepts of Chemistry MCQs with Answers

These public questions are selected from the exact Some Basic Concepts of Chemistry chapter, screened for topic relevance and deduplicated so repeated versions of the same MCQ are not shown publicly. Use them for quick revision, then sign in to attempt the complete test experience with more questions, results and performance review.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

1. One mole contains:

  • A. 3.011×10²³
  • B. 6.022×10²³
  • C. 9.11×10²³
  • D. 1.00×10²³
Answer: B
Explanation: One mole contains Avogadro's number of entities.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

2. The molar mass of H₂SO₄ is:

  • A. 96
  • B. 98
  • C. 100
  • D. 102
Answer: B
Explanation: 2(1)+32+4(16)=98 g mol⁻¹.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

3. At STP, 0.5 mol of an ideal gas occupies:

  • A. 5.6 L
  • B. 11.2 L
  • C. 22.4 L
  • D. 44.8 L
Answer: B
Explanation: 0.5×22.4=11.2 L.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

4. The empirical formula represents:

  • A. Actual number of atoms
  • B. Simplest whole-number ratio
  • C. Molecular mass
  • D. Valency only
Answer: B
Explanation: It gives the simplest whole-number atomic ratio.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

5. The limiting reagent is the reactant that:

  • A. Remains after reaction
  • B. Is consumed first
  • C. Has highest molar mass
  • D. Acts as catalyst
Answer: B
Explanation: It is used up first and limits product formation.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

6. Molarity is defined as:

  • A. mol solute/kg solvent
  • B. mol solute/L solution
  • C. g solute/L solvent
  • D. mol solvent/L solution
Answer: B
Explanation: M=n/V in litres of solution.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

7. Molality is defined as:

  • A. mol solute/L solution
  • B. mol solute/kg solvent
  • C. g solute/L solution
  • D. mol solvent/kg solute
Answer: B
Explanation: Molality uses kilograms of solvent.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

8. Which concentration term is independent of temperature?

  • A. Molarity
  • B. Molality
  • C. Normality
  • D. g L⁻¹
Answer: B
Explanation: Molality depends on masses, not volume.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

9. A solution with 1 mol solute and 4 mol solvent has solute mole fraction:

  • A. 0.20
  • B. 0.25
  • C. 0.50
  • D. 0.80
Answer: A
Explanation: x=1/(1+4)=0.20.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

10. The law of definite proportions states that:

  • A. Mass is conserved
  • B. A compound has fixed elemental mass ratio
  • C. Gas volumes combine simply
  • D. Atoms are divisible
Answer: B
Explanation: A pure compound always has fixed composition.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

11. CO and CO₂ illustrate:

  • A. Definite proportions
  • B. Multiple proportions
  • C. Reciprocal proportions
  • D. Avogadro's law
Answer: B
Explanation: Oxygen masses combining with fixed carbon are in a simple ratio.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

12. In 2H₂ + O₂ → 2H₂O, 3 mol O₂ can produce:

  • A. 3 mol H₂O
  • B. 4 mol H₂O
  • C. 6 mol H₂O
  • D. 8 mol H₂O
Answer: C
Explanation: 1 mol O₂ gives 2 mol H₂O.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

13. 36 g of water corresponds to:

  • A. 1 mol
  • B. 2 mol
  • C. 3 mol
  • D. 4 mol
Answer: B
Explanation: 36/18=2 mol.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

14. 0.25 mol CO₂ contains molecules:

  • A. 1.506×10²³
  • B. 3.011×10²³
  • C. 6.022×10²³
  • D. 12.044×10²³
Answer: A
Explanation: 0.25×6.022×10²³=1.506×10²³.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

15. 18 g H₂O contains total atoms:

  • A. 6.022×10²³
  • B. 1.204×10²⁴
  • C. 1.807×10²⁴
  • D. 3.011×10²³
Answer: C
Explanation: 1 mol H₂O has 3 mol atoms.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

16. The percentage by mass of oxygen in H₂O is:

  • A. 11.11%
  • B. 50%
  • C. 88.89%
  • D. 94.12%
Answer: C
Explanation: 16/18×100=88.89%.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

17. A compound contains 40% C, 6.67% H and 53.33% O. Its empirical formula is:

  • A. CH₂O
  • B. C₂H₄O₂
  • C. CH₄O
  • D. CHO
Answer: A
Explanation: Mole ratio C:H:O = 1:2:1.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

18. If empirical formula is CH₂O and molar mass is 180, molecular formula is:

  • A. CH₂O
  • B. C₂H₄O₂
  • C. C₆H₁₂O₆
  • D. C₃H₆O₃
Answer: C
Explanation: 180/30=6, so (CH₂O)₆.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

19. A 10 g sample is 80% pure. Pure substance present is:

  • A. 2 g
  • B. 8 g
  • C. 10 g
  • D. 12.5 g
Answer: B
Explanation: 10×0.80=8 g.

CBSE Class 11 Chemistry · Some Basic Concepts of Chemistry · Very Very Hard

20. Actual yield is 18 g and theoretical yield is 24 g. Percentage yield is:

  • A. 25%
  • B. 50%
  • C. 75%
  • D. 80%
Answer: C
Explanation: 18/24×100=75%.

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How should I prepare Some Basic Concepts of Chemistry for CBSE Class 11 Chemistry?

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