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JEE Main 2021 — Thermodynamics (C) Question with Solution

JEE Main 2021 (18 Mar Shift 2)

Question

The gas phase reaction

2 Ag⇌A2g

at 400 K has ΔGo=+25.2 kJ mol-1.

The equilibrium constant KC for this reaction is ___ ×10-2. (Round off to the Nearest integer)

Use : R=8.3 J mol-1 K-1,ln10=2.3 log102=0.30, 1 atm=1 bar

             antilog (-0.3)=0.501

Enter your answer

Show full solutionCorrect answer: 2
Correct answer
2

Step-by-step explanation

Using formula

ΔrG0=-RTlnKp

25200=-2.3×8.3×400logKp

Kp=10-3.3=10-3×0.501

=5.01×10-4Bar-1

=5.01×10-9 Pa-1

=KC8.3×400

KC=1.66×10-5 m3/mole

=1.66×10-2 L/mol

=2

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 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.