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Friday, 9 October

NEET UG 2020 · Chemistry · Question 127

NEET 2020 Chemistry, question 127

Question 127 of the NEET 2020 paper (code E1) is a Chemistry question from Thermodynamics. Its idea, Entropy Change Prediction, was asked 3 times, in 2019, 2020 and 2024, across NEET 2017–2026. The NTA final answer key gives option 4.

Updated 2026-10-08

Q127 · Chemistry

For the reaction, 2Cl(g)→Cl2(g)\mathrm{2Cl(g) \to Cl_2(g)}, the correct option is :

  1. 1ΔrH>0\Delta_rH > 0 and ΔrS>0\Delta_rS > 0
  2. 2ΔrH>0\Delta_rH > 0 and ΔrS<0\Delta_rS < 0
  3. 3ΔrH<0\Delta_rH < 0 and ΔrS>0\Delta_rS > 0
  4. 4ΔrH<0\Delta_rH < 0 and ΔrS<0\Delta_rS < 0Official answer

Official answer: option 4 · NTA final answer key

Same idea

Entropy Change Prediction, in other papers

NEET asked this idea 3 times, in 2019, 2020 and 2024. The other 2 questions below.

  • 2024 Q61In which of the following processes entropy increases? A. A liquid evaporates to vapour. B. Temperature of a crystalline solid lowered…Other · Easy
  • 2019 Q86In which case change in entropy is negative ?One-line MCQ · Easy

Entropy Change Prediction: every question and how it was framed

The chapter

Thermodynamics in ten years of NEET

32 questions from 2017–2026, asked in 10 of 10 papers, about 3.1 a paper. Gibbs Free Energy alone had 7.

Chapter analysisStudy this chapterPractise this chapter

Thermodynamics: questions per paper

0364’174’183’193’202’212’222’234’243’255’26