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JEE Main 2020 — Thermodynamics (C) Question with Solution

JEE Main 2020 (07 Jan Shift 1)

Question

For the reaction;
Al→2Bg
ΔU=2.1kcal,ΔS=20calK-1 at 300K.
Hence ΔG in kcal is _____________.

Enter your answer

Show full solutionCorrect answer: -2.7
Correct answer
-2.7

Step-by-step explanation

∆H=∆U+∆ngRT
=2.1×103+22300
=2100+1200
=3300cal
∆G=∆H-T∆S
=3300-30020
=3300-6000
=-2700cals=-2.7kcal

Gibbs free energy can be visualized as the amount of useful energy present in a thermodynamic system that can be utilized to perform some useful work.

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About this question

This is a previous-year question from JEE Main 2020, 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.