PYQ Vault
EbooksTutor

Electrochemistry

JEE Mains Chemistry. Try each one first, then open its answer.

Top 10 JEE Mains PYQs to practise first

The questions and kinds of question asked most often come first. Each one says how often and in which papers.

  1. Question 1

    This type asked 6 times: 28 Jun 2022, 10 Apr 2023, 11 Apr 2023, 23 Jan 2025, 24 Jan 2025, 8 Apr 2026 S2. This one: 8 Apr 2026 S2 See all 6 of this type

    31
    Given at 298 K:EFe2+/Fe⊖=X298\text{ }K:E_{Fe^{2 +}/Fe}^{\ominus}= X Volt
    EFe3+/Fe⊖=Y Volt E_{Fe^{3 +}/Fe}^{\ominus}= Y\text{~Volt~}
    The EFe3+/Fe2+⊖E_{Fe^{3 +}/Fe^{2 +}}^{\ominus} in Volt at 298 K is given by :

    Tap an option to check your answer.

  2. Question 2

    This type asked 5 times: 2021 Paper 21, 29 Jul 2022, 31 Jan 2023, 2 Apr 2025, 5 Apr 2026 S2. This one: 5 Apr 2026 S2 See all 5 of this type

    49
    At 298 K , the molar conductivity of x%(w/w)x\%(w/w) MX solution (aqueous) is 123.5 S cm2 mol−1123.5\text{ }S{\text{ }cm}^{2}{\text{ }mol}^{- 1}. The conductance of same solution is 1.9×10−3 S1.9 \times 10^{- 3}\text{ }S. The value of xx is ____\_\_\_\_ ×10−2\times 10^{- 2}. (Given : cell constant =1.3 cm−1= 1.3{\text{ }cm}^{- 1}; molar mass of MX is 75 g mol−175\text{ }g{\text{ }mol}^{- 1}, density of aqueous solution of MX at 298 K is 1.0 g mL−11.0\text{ }g{\text{ }mL}^{- 1} )

  3. Question 3

    This type asked 5 times: 2021 Paper 17, 2021 Paper 19, 2021 Paper 26, 30 Jan 2023, 22 Jan 2026 S1. This one: 22 Jan 2026 S1 See all 5 of this type

    47
    Consider the following electrochemical cell at 298 K Pt∣HSnO2−(aq)∣Sn(OH)6 2−(aq)∣Bi2O3(s)∣Bi(s)Pt\left| {HSnO}_{2}^{-}(aq) \right|Sn(OH)_{6}\ ^{2 -}(aq)\left| {Bi}_{2}O_{3}(s) \right|Bi(s). If the reaction quotient at a given time is 10610^{6}, then the cell EMF (Ecell E_{\text{cell~}}) is ____\_\_\_\_ ×10−1 V\times 10^{- 1}\text{ }V (Nearest integer). Given the standard half-cell reduction potential as EBi2O3/Bi,OH−0=−0.44 VE_{{Bi}_{2}O_{3}/{Bi}_{,{OH}^{-}}}^{0} = - 0.44\text{ }V and
    ESn(OH)62−/HSnO2−,OH0=−0.90 VE_{Sn(OH)_{6}^{2 -}/{HSnO}_{2}^{-},OH}^{0} = - 0.90\text{ }V

  4. Question 4

    This type asked 5 times: 2021 Paper 25, 28 Jun 2022, 26 Jul 2022, 31 Jan 2024, 1 Feb 2024. This one: 1 Feb 2024 See all 5 of this type

    147
    The amount of electricity in Coulomb required for the oxidation of 1 mol1\text{ }mol of H2OH_{2}O to O2O_{2} is ______ ×105C\times10^{5}C.

  5. Question 5

    This type asked 4 times: 14 Jun 2022, 29 Jun 2022, 29 Jul 2022, 5 Apr 2026 S2. This one: 5 Apr 2026 S2 See all 4 of this type

    32
    One half cell in a voltaic cell is constructed by dipping silver rod in AgNO3AgNO_{3} solution of unknown concentration, other half cell is Zn rod dipped in 1 molar solution of ZnSO4ZnSO_{4}. A voltage of 1.60 V is measured at 298 K for this cell. What is the concentration of Ag+Ag^{+}ions used in terms of log⁡x(x=[Ag+])\log x\left( x =\left\lbrack Ag^{+} \right\rbrack \right)? EZn2+/ZnΘ=−0.76 V,EAg+/AgΘ=+0.80 VE_{Zn^{2 +}/Zn}^{\Theta}= - 0.76\text{ }V,E_{Ag^{+}/Ag}^{\Theta}= + 0.80\text{ }V, 2.303RTF=0.059 V\frac{2.303RT}{F}= 0.059\text{ }V

    Tap an option to check your answer.

  6. Question 6

    This type asked 4 times: 10 Apr 2023, 4 Apr 2025, 21 Jan 2026 S1, 24 Jan 2026 S2. This one: 24 Jan 2026 S2 See all 4 of this type

    49
    Molar conductivity of a weak acid HQ of concentration 0.18 M was found to be 1/301/30 of the molar conductivity of another weak acid HZ with concentration of 0.02 M. If λQ−0\lambda_{Q^{-}}^{0} happened to be equal with λZ−0\lambda_{Z^{-}}^{0}, then the difference of the pKa{pK}_{a} values of the two weak acids (pKa(HQ)−pKa(HZ))\left( {pK}_{a}(HQ) - {pK}_{a}(HZ) \right) is ____\_\_\_\_ (Nearest integer). [Given : degree of dissociation (α)≪1(\alpha) \ll 1 for both weak acids, λ∘\lambda^{\circ} : limiting molar conductivity of ions]

  7. Question 7

    This type asked 4 times: 2021 Paper 18, 27 Jul 2022, 15 Apr 2023, 29 Jan 2025. This one: 29 Jan 2025 See all 4 of this type

    28
    The molar conductivity of a weak electrolyte when plotted against the square root of its concentration, which of the following is expected to be observed?

    Tap an option to check your answer.

  8. Question 8

    This type asked 4 times: 25 Jun 2022, 13 Apr 2023, 29 Jan 2024, 22 Jan 2025. This one: 22 Jan 2025 See all 4 of this type

    26
    A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A . The amount of the aluminium deposited at the cathode is ___\_\_\_ .[Given : molar mass of aluminium and chlorine are 27 g mol−127\text{ }g{\text{ }mol}^{- 1} and 35.5 g mol−135.5\text{ }g{\text{ }mol}^{- 1} respectively, Faraday constant  =96500Cmol−1]\left. \ = 96500Cmol^{- 1} \right\rbrack.

    Tap an option to check your answer.

  9. Question 9

    This type asked 3 times: 28 Jun 2022, 1 Feb 2023, 6 Apr 2026 S1. This one: 6 Apr 2026 S1 See all 3 of this type

    33
    Consider the following data :
    ElectrolyteΛm∘\Lambda_{m}^{\circ} (S cm2 mol−1S\ cm^{2}\ mol^{-1})
    BaCl2BaCl_{2}x1x_{1}
    H2SO4H_{2}SO_{4}x2x_{2}
    HClHClx3x_{3}
    BaSO4BaSO_{4} is sparingly soluble in water. If the conductivity of the saturated BaSO4BaSO_{4} solution is x S cm−1x\ S\ cm^{-1}, then the solubility product of BaSO4BaSO_{4} can be given as (here Λm=Λm∘\Lambda_{m} = \Lambda_{m}^{\circ}) :

    Tap an option to check your answer.

  10. Question 10

    This type asked 3 times: 25 Jun 2022, 5 Apr 2024, 2 Apr 2026 S1. This one: 2 Apr 2026 S1 See all 3 of this type

    32
    An electrochemical cell is constructed using half cells in the direction of spontaneous change: Fe(OH)2( s)+2e−→Fe(s)+2OH−(aq) E0=−0.88 VFe(OH)_{2}(\text{ }s) + 2e^{-}\rightarrow Fe(s) + 2OH^{-}(aq)\ E^{0}= - 0.88\text{ }V and AgBr(s)+e−→Ag(s)+Br−(aq) E0=+0.07 VAgBr(s) +e^{-}\rightarrow Ag(s) +Br^{-}(aq)\ E^{0}= + 0.07\text{ }V Which of the following option is correct?

    Tap an option to check your answer.