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Chemistry

Chemical Thermodynamics

A Chemistry chapter of the NEET syllabus, and how to practise it for the computer-based exam.

Exam rules change between cycles. Confirm dates, syllabus and pattern against NTA's official site. We are not NTA.

Weightage: what the paper actually did

Chemical Thermodynamics carried 5 questions in the NEET 2026 paper. One paper is a data point, not a destiny: NTA moves weight between chapters every cycle, which is why the weightage tables deserve care. The stable facts are the paper's shape: 180 questions, 720 marks, +4 right, −1 wrong.

Sample PYQs from this chapter

Real questions NTA asked from Chemical Thermodynamics, with the answer and the working. Try before you peek.

Question 1 · NEET 2026

At a certain temperature, T (K), during a process, 500 J is absorbed by the system and work of 200 J is done by the system. Then change in internal energy of the system is:
  1. A.400 J
  2. B.300 J
  3. C.700 J
  4. D.500 J
Answer and explanation

Answer: B

By the first law of thermodynamics, ΔU=q+w\Delta U = q + w. Heat absorbed by the system gives q = +500 J, and work done by the system gives w = -200 J. Therefore ΔU=500−200=300\Delta U = 500 - 200 = 300 J.

Question 2 · NEET 2020

For the reaction 2Cl(g) → Cl2_{2}(g), the correct option is
  1. A.Δ\DeltarH > 0 and Δ\DeltarS < 0
  2. B.Δ\DeltarH < 0 and Δ\DeltarS > 0
  3. C.Δ\DeltarH < 0 and Δ\DeltarS < 0
  4. D.Δ\DeltarH > 0 and Δ\DeltarS > 0
Answer and explanation

Answer: C

The reaction 2Cl(g)→Cl2(g)2\mathrm{Cl}(\text{g}) → \mathrm{Cl}_2(\text{g}) involves the formation of a bond, which releases energy, making ΔrH<0\Delta_r H < 0. Additionally, the reaction decreases the number of gas molecules, reducing entropy, so ΔrS<0\Delta_r S < 0. Chapter: Chemical Thermodynamics.

How to practise Chemical Thermodynamics

Chapter by chapter, against real past-paper questions, on a screen: NEET is computer based from 2027. Read the chapter once, then attempt its PYQs until your accuracy stops climbing, and let the wrong answers tell you which lines to reread. If the chapter keeps refusing to stick, that has its own guide. There is also a free NEET mini mock with answers.

Nearby Chemistry chapters

Questions

How many questions did Chemical Thermodynamics have in NEET 2026?

Chemical Thermodynamics carried 5 questions in the NEET 2026 paper. Weightage shifts between cycles, so treat it as a probability, not a promise.

Where can I practise Chemical Thermodynamics PYQs for NEET?

Explore available chapter-wise NEET practice in BrainIt, free until the 2027 exam. Review explanations and track chapter accuracy to guide your revision. Sample questions from this chapter are on this page.

Is Chemical Thermodynamics important for NEET 2027?

It is part of the Chemistry syllabus the paper draws from, and NEET 2027 is computer based, so practise it on a screen. Your own accuracy in the chapter matters more than any weightage table: a heavy chapter you already score well on needs less time than a light one you keep missing.

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