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Friday, 9 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueHardMulti-step

JEE Main 18 March 2021, Shift 1, Chemistry Q56

Question 56 of 90 in this shift, Chemistry question 26 of 30, Section B.

For the reaction 2Fe3+(aq)+2I−(aq)→2Fe2+(aq)+I2(s)\mathrm{2Fe^{3+}(aq) + 2I^-(aq) \rightarrow 2Fe^{2+}(aq) + I_2(s)} the magnitude of the standard molar free energy change, ΔrGm∘=−\Delta_rG^\circ_m = - __________ kJ (Round off to the Nearest Integer). [EFe2+/Fe(s)∘=−0.440 V; EFe3+/Fe(s)∘=−0.036 V; EI2/2I−∘=0.539 V; F=96500 C]\left[E^\circ_{Fe^{2+}/Fe(s)} = -0.440\ \mathrm{V};\ E^\circ_{Fe^{3+}/Fe(s)} = -0.036\ \mathrm{V};\ E^\circ_{I_2/2I^-} = 0.539\ \mathrm{V};\ F = 96500\ \mathrm{C}\right]

Official answer

45

NTA final key.

Chapter
Electrochemistry
Topic
Gibbs Free Energy
Idea tested
Standard Gibbs Energy and Standard Cell Potential

Same topic in other shifts

All Gibbs Free Energy questions
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  2. 2 Apr 2026, Shift 2 · Q73Consider the following two half-cell reactions along with the standard reduction potential given:…HardNumerical value
  3. 4 Apr 2026, Shift 2 · Q72For the following reaction at 50 ∘^\circC and at 2 atm pressure, 2N2O5(g)⇌2N2O4(g)+O2(g)\mathrm{2N_2O_5(g)\rightleftharpoons2N_2O_4(g)+O_2(g)}…HardNumerical value
  4. 5 Apr 2026, Shift 2 · Q54Consider the following data for the reaction X2(g)+Y2(g)⇌2XY(g)\mathrm{X_2(g)+Y_2(g)\rightleftharpoons 2XY(g)} at 600 K. The ΔrG⊖\Delta_r G^\ominus (in kJ…MediumSingle correct
  5. 6 Apr 2026, Shift 1 · Q75Consider the reaction X⇌Y\mathrm{X\rightleftharpoons Y} at 300 K. If ΔHθ\Delta H^\theta and K are 28.40 kJ mol−1^{-1} and 1.8×10−71.8\times10^{-7}…MediumNumerical value
  6. 2 Apr 2025, Shift 2 · Q54Which of the following graphs correctly represents the variation of thermodynamic properties of Haber's process ?HardDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.