JEE Main 2021 · ChemistryNumerical answerNumerical valueHardCalculation

JEE Main 25 July 2021, Shift 1, Chemistry Q58

Question 58 of 90 in this shift, Chemistry question 28 of 30, Section B.

Consider the cell at 25

^\circ

\mathrm{Zn|Zn^{2+}(aq),(1\ M)\,||\,Fe^{3+}(aq),Fe^{2+}(aq)|Pt(s)}

The fraction of total iron present as

\mathrm{Fe^{3+}}

ion at the cell potential of 1.500 V is

x\times10^{-2}

. The value of

x

is _________. (Nearest integer) (Given :

E^0_{\mathrm{Fe^{3+}/Fe^{2+}}}=0.77

E^0_{\mathrm{Zn^{2+}/Zn}}=-0.76

Official answer

NTA final key.

Chapter: Electrochemistry
Topic: Nernst Equation
Idea tested: Full Cell Nernst Equation

Same idea in other shifts

Asked 6× in all

4 Apr 2026, Shift 2 · Q73An electrochemical cell, consist of the following two redox couples, $\mathrm{M^{x+}(aq)/M(s)}$ $[E^\ominus_{red}=+0.15\ \mathrm{V}]$ and…HardNumerical value
5 Apr 2026, Shift 2 · Q57One half cell in a voltaic cell is constructed by dipping silver rod in $\mathrm{AgNO_3}$ solution of unknown concentration, other half…MediumSingle correct
7 Apr 2025, Shift 1 · Q711 Faraday electricity was passed through $\mathrm{Cu^{2+}}$ (1.5 M, 1 L) /Cu and 0.1 Faraday was passed through $\mathrm{Ag^+}$ (0.2 M, 1…HardNumerical valueHas a figure
25 Jul 2022, Shift 1 · Q84The cell potential for $\mathrm{Zn|Zn^{2+}(aq)\|Sn^{x+}|\,Sn}$ is $0.801$ V at 298 K. The reaction quotient for the above reaction is…MediumNumerical value
24 Jun 2022, Shift 1 · Q84The cell potential for the following cell $\mathrm{Pt\,|H_2(g)|H^+(aq)\|\ Cu^{2+}(0.01\ M)|Cu(s)}$ is 0.576 V at 298 K. The pH of the…MediumNumerical value

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.