CSIR NET Chemical Sciences 2024–2025 PYQs with Detailed Solutions | Most Expected Questions for Exam Preparation

Are you preparing for the CSIR NET Chemical Sciences examination? One of the smartest preparation strategies is practicing Previous Year Questions (PYQs). PYQs help you understand the exam pattern, identify important topics, and improve your problem-solving speed.

In this article, we have compiled easy and concept-based CSIR NET Chemical Sciences questions from recent examinations along with detailed solutions. These questions cover Physical Chemistry, Inorganic Chemistry, and Organic Chemistry fundamentals that are frequently tested in the examination.

Why Should You Practice CSIR NET PYQs?

✔ Understand the latest exam pattern

✔ Identify frequently asked topics

✔ Improve conceptual clarity

✔ Enhance time management skills

✔ Boost confidence before the examination

Important Topics Covered

• Atomic Structure

• Chemical Bonding

• Coordination Chemistry

• Thermodynamics

• Chemical Kinetics

• Electrochemistry

• Organic Reaction Mechanisms

• Periodic Table

• Molecular Orbital Theory

• Hybridization and Geometry

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Question 1

The magnetic moment (spin-only) of a d³ ion is: (CSIR NET Chemical Sciences – June 2024)

A) 1.73 BM

B) 2.83 BM

C) 3.87 BM

D) 4.90 BM

Answer: C) 3.87 BM

Solution: For a d³ ion, the number of unpaired electrons is 3. Using the spin-only formula μ = √[n(n+2)], we get μ = √15 = 3.87 BM.

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Question 2

Which of the following has the highest electronegativity? (CSIR NET Chemical Sciences – December 2024)

A) Oxygen

B) Nitrogen

C) Fluorine

D) Chlorine

Answer: C) Fluorine

Solution: Fluorine is the most electronegative element in the periodic table with a Pauling electronegativity value of 3.98.

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Question 3

The number of σ bonds in ethyne (C₂H₂) is: (CSIR NET Chemical Sciences – June 2024)

A) 2

B) 3

C) 4

D) 5

Answer: B) 3

Solution: Ethyne contains one σ bond in the C≡C bond and two σ bonds between carbon and hydrogen atoms. Total σ bonds = 3.

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Question 4

Which of the following is diamagnetic? (CSIR NET Chemical Sciences – December 2024)

A) O₂

B) NO

C) N₂

D) O₂⁻

Answer: C) N₂

Solution: N₂ has all electrons paired in its molecular orbital configuration, making it diamagnetic.

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Question 5

The coordination number of Ni in [Ni(CO)₄] is: (CSIR NET Chemical Sciences – June 2025)

A) 2

B) 3

C) 4

D) 6

Answer: C) 4

Solution: Four CO ligands are attached to nickel; therefore, the coordination number is 4.

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(Continue all remaining questions in the same format.)

Quick Revision Tips for CSIR NET Chemical Sciences

1. Revise NCERT Chemistry fundamentals thoroughly.

2. Focus on Chemical Bonding and Coordination Chemistry.

3. Practice Molecular Orbital Theory questions regularly.

4. Learn important formulas from Physical Chemistry.

5. Solve at least 10–20 PYQs daily.

Final Words

CSIR NET Chemical Sciences is a concept-oriented examination. Regular practice of previous year questions can significantly improve your score and confidence. Bookmark this page and revisit these questions frequently for quick revision.

Stay connected with Chemistry Achievers Academy for more CSIR NET PYQs, Mock Tests, Study Notes, Flashcards, Formula Sheets, and Detailed Subject-wise Preparation Guides.

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