JEE Main 2020 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 8 January 2020, Shift 1, Chemistry Q48

Question 48 of 75 in this shift, Chemistry question 23 of 25, Section B.

What would be the electrode potential for the given half cell reaction at pH=5 ? ______.

2\mathrm{H_2O} \rightarrow \mathrm{O_2} + 4\mathrm{H}^{\oplus} + 4e^{-}

;

E^0_{red} = 1.23\ \mathrm{V}

(

R = 8.314\ \mathrm{J\ mol^{-1}\ K^{-1}}

; Temp

= 298\ \mathrm{K}

; oxygen under std. atm. pressure of 1 bar)

Official answer

-0.93 to -0.94

NTA final key (Jan 2020). Any value in the range scored.

Chapter: Electrochemistry
Topic: Nernst Equation
Idea tested: pH Dependence of Electrode Potential

Same idea in other shifts

Asked 6× in all

8 Apr 2025, Shift 2 · Q75Consider the following half cell reaction $\mathrm{Cr_2O_7^{2-}(aq) + 6e^- + 14H^+(aq) \longrightarrow 2Cr^{3+}(aq) + 7H_2O(l)}$ The…MediumNumerical value
29 Jun 2022, Shift 2 · Q84The cell potential for the given cell at 298 K $\mathrm{Pt|H_2\,(g,1\ bar)|H^{+}\,(aq)||Cu^{2+}\,(aq)|Cu(s)}$ is 0.31V. The pH of the…MediumNumerical value
30 Jun 2022, Shift 1 · Q65In which of the following half cells, electrochemical reaction is pH dependent ?EasySingle correct
24 Feb 2021, Shift 2 · Q56The magnitude of the change in oxidising power of the $\mathrm{MnO_4^-/Mn^{2+}}$ couple is $x \times 10^{-4}$ V, if the $\mathrm{H^+}$ …MediumNumerical value
25 Feb 2021, Shift 2 · Q56Copper reduces $\mathrm{NO_3^-}$ into NO and $\mathrm{NO_2}$ depending upon the concentration of $\mathrm{HNO_3}$ in solution. (Assuming…HardNumerical 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 108 of the 174 JEE Main shifts held from 2017 to 2026.