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Saturday, 31 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 3 August 2021, Shift 1, Chemistry Q56

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

The logarithm of equilibrium constant (log⁡10\log_{10}K) for the reaction Pd(aq)2++4Cl(aq)−⇌PdCl42−(aq)\mathrm{Pd^{2+}_{(aq)} + 4Cl^{-}_{(aq)} \rightleftharpoons PdCl_4^{2-}{}_{(aq)}} is xx × 10−110^{-1}. The value of xx is ________. (Nearest integer) [Given emf for the half-cell at 25ºC Pd(aq)2++2e−⟶Pd(s)\mathrm{Pd^{2+}_{(aq)} + 2e^{-} \longrightarrow Pd_{(s)}} Eº = 0.83V PdCl42−(aq)+2e−⟶Pd(s)+4Cl−\mathrm{PdCl_4^{2-}{}_{(aq)} + 2e^{-} \longrightarrow Pd(s) + 4Cl^{-}} Eº = 0.64V]

Official answer

64

NTA final key.

Chapter
Electrochemistry
Topic
Nernst Equation
Idea tested
E°cell and Equilibrium

Same idea in other shifts

Asked 4× in all
  1. 1 Feb 2024, Shift 2 · Q85Consider the following redox reaction : MnO4−+H++H2C2O4⇌Mn2++H2O+CO2\mathrm{MnO_4^- + H^+ + H_2C_2O_4 \rightleftharpoons Mn^{2+} + H_2O + CO_2} The standard…MediumNumerical value
  2. 4 Aug 2021, Shift 2 · Q58The standard electrode potentials of the reactions are given below.…MediumNumerical value
  3. 8 Jan 2020, Shift 2 · Q48For an electrochemical cell Sn(s)∣Sn2+(aq, 1M)∣∣Pb2+(aq, 1M)∣Pb(s)\mathrm{Sn(s)|Sn^{2+}(aq,\ 1M)||Pb^{2+}(aq,\ 1M)|Pb(s)} the ratio…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 108 of the 174 JEE Main shifts held from 2017 to 2026.