JEE Main 2021ChemistryThermodynamics (C)HardNumerical

JEE Main 2021 — Thermodynamics (C) Question with Solution

JEE Main 2021 (20 Jul Shift 2)

Question

For a given chemical reaction A→B at 300 K the free energy change is -49.4 kJ mol-1 and the enthalpy of reaction is 51.4 kJ mol-1. The entropy change of the reaction is _________JK-1 mol-1.

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Show full solutionCorrect answer: 336
Correct answer
336

Step-by-step explanation

Given chemical reaction:

A⟶T=300 KB[ΔG]P,T=-49.4 kJ/mol

ΔHrxn=51.4 kJ/mol

ΔSrxn=?

⇒From the relation [ΔG]P,T=ΔH-TΔS

⇒ΔSrxn=ΔHrxn-[ΔG]P,TT

=[51.4-(-49.4)]×1000300JmolK

⇒ΔSrxn=336JmolK

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About this question

This is a previous-year question from JEE Main 2021, covering the Thermodynamics (C) chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.