NEET Electrochemistry PYQ practice sheet

15 previous-year NEET Chemistry questions from Electrochemistry, newest papers first. Electrochemistry carries 15 of the Chemistry questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

1. 1.

   RE-NEET 2026

   The standard electrode potential ($E^\circ$) for the half-cell reaction $\mathrm{Fe^{3+} + e^- \rightarrow Fe^{2+}}$ at $298$ K is (Given : $E^\circ(\mathrm{Fe^{3+}/Fe}) = -0.04$ V and $E^\circ(\mathrm{Fe^{2+}/Fe}) = -0.44$ V at $298$ K)

   • (A)
     $+0.76$ V
   • (B)
     $-0.48$ V
   • (C)
     $+0.92$ V
   • (D)
     $+0.40$ V
2. 2.

   RE-NEET 2026

   For a salt $\mathbf{XY}$, which is a strong electrolyte, the plot of $\Lambda_m$ versus $\sqrt{c}$ has a slope of $-90.0\ \mathrm{S\,cm^2\,mol^{-3/2}\,L^{1/2}}$ at $298$ K. At $0.01$ M concentration of $\mathbf{XY}$, the value of $\Lambda_m$ is $145.0\ \mathrm{S\,cm^2\,mol^{-1}}$. The limiting molar conductivity of $\mathbf{Y^-}$ ion ($\lambda^0_{Y^-}$, in $\mathrm{S\,cm^2\,mol^{-1}}$) at $298$ K will be (Given : $\lambda^0_{X^+} = 74.0\ \mathrm{S\,cm^2\,mol^{-1}}$)

   • (A)
     $80.0$
   • (B)
     $90.0$
   • (C)
     $100.0$
   • (D)
     $76.0$
3. 3.

   NEET 2026

   A solution of copper sulphate is electrolysed for 10 minutes with a current of 1.5 amperes. The mass of copper deposited at cathode is: (Given: molar mass of Cu = 63 g mol$^{-1}$; $1\ \text{F}=96487\ \text{C mol}^{-1}$)

   • (A)
     2.4036 g
   • (B)
     1.7018 g
   • (C)
     0.2938 g
   • (D)
     0.5876 g
4. 4.

   NEET 2026

   Calculate emf of the half cell given below: $\mathrm{Pt(s)\,|\,H_2(g,\ 2\ atm)\,|\,HCl(aq,\ 0.02\ M)}$, $E^\circ_{\mathrm{H^+/H_2}}=0$ V (Given: $\dfrac{2.303RT}{F}=0.059$, $\log2=0.3010$)

   • (A)
     0.035 V
   • (B)
     –0.035 V
   • (C)
     0.109 V
   • (D)
     –0.109 V
5. 5.

   NEET 2024

   Match List-I with List-II. List-I (Conversion): (A) 1 mol of $\mathrm{H_2O}$ to $\mathrm{O_2}$, (B) 1 mol of $\mathrm{MnO_4^-}$ to $\mathrm{Mn^{2+}}$, (C) 1.5 mol of Ca from molten $\mathrm{CaCl_2}$, (D) 1 mol of FeO to $\mathrm{Fe_2O_3}$ List-II (Number of Faraday required): (I) 3F, (II) 2F, (III) 1F, (IV) 5F Choose the correct answer from the options given below:

   • (A)
     A-II, B-IV, C-I, D-III
   • (B)
     A-II, B-III, C-I, D-IV
   • (C)
     A-III, B-IV, C-II, D-I
   • (D)
     A-III, B-IV, C-I, D-II
6. 6.

   NEET 2024

   Mass in grams of copper deposited by passing 9.6487 A current through a voltameter containing copper sulphate solution for 100 seconds is: (Given: molar mass of Cu: $63\ \mathrm{g\ mol^{-1}}$, $1\,\mathrm{F}=96487\ \mathrm{C}$)

   • (A)
     0.0315 g
   • (B)
     31.5 g
   • (C)
     0.315 g
   • (D)
     3.15 g
7. 7.

   NEET 2023

   The conductivity of centimolar solution of $\mathrm{KCl}$ at $25^\circ\mathrm{C}$ is $0.0210\ \mathrm{ohm^{-1}\,cm^{-1}}$ and the resistance of the cell containing the solution at $25^\circ\mathrm{C}$ is $60\ \mathrm{ohm}$. The value of cell constant is -

   • (A)
     $3.34\ \mathrm{cm^{-1}}$
   • (B)
     $1.34\ \mathrm{cm^{-1}}$
   • (C)
     $3.28\ \mathrm{cm^{-1}}$
   • (D)
     $1.26\ \mathrm{cm^{-1}}$
8. 8.

   NEET 2023

   Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R : Assertion A : In equation $\Delta_rG = -nFE_{cell}$, value of $\Delta_rG$ depends on $n$. Reasons R : $E_{cell}$ is an intensive property and $\Delta_rG$ is an extensive property. In the light of the above statements, choose the correct answer from the options given below :

   • (A)
     A is false but R is true.
   • (B)
     Both A and R are true and R is the correct explanation of A.
   • (C)
     Both A and R are true but R is NOT the correct explanation of A.
   • (D)
     A is true but R is false.
9. 9.

   NEET 2022

   At 298 K, the standard electrode potentials of $\mathrm{Cu^{2+}/Cu}$, $\mathrm{Zn^{2+}/Zn}$, $\mathrm{Fe^{2+}/Fe}$ and $\mathrm{Ag^{+}/Ag}$ are 0.34 V, $-0.76$ V, $-0.44$ V and 0.80 V, respectively. On the basis of standard electrode potential, predict which of the following reaction cannot occur:

   • (A)
     $2\mathrm{CuSO_4(aq)}+2\mathrm{Ag(s)}\rightarrow2\mathrm{Cu(s)}+\mathrm{Ag_2SO_4(aq)}$
   • (B)
     $\mathrm{CuSO_4(aq)}+\mathrm{Zn(s)}\rightarrow\mathrm{ZnSO_4(aq)}+\mathrm{Cu(s)}$
   • (C)
     $\mathrm{CuSO_4(aq)}+\mathrm{Fe(s)}\rightarrow\mathrm{FeSO_4(aq)}+\mathrm{Cu(s)}$
   • (D)
     $\mathrm{FeSO_4(aq)}+\mathrm{Zn(s)}\rightarrow\mathrm{ZnSO_4(aq)}+\mathrm{Fe(s)}$
10. 10.

    NEET 2022

    Given below are half cell reactions:

    $$\mathrm{MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O},\quad E^\circ_{\mathrm{Mn^{2+}/MnO_4^-}}=-1.510\ \text{V}$$

    $$\dfrac{1}{2}\mathrm{O_2 + 2H^+ + 2e^- \rightarrow H_2O},\quad E^\circ_{\mathrm{O_2/H_2O}}=+1.223\ \text{V}$$

    Will the permanganate ion, $\mathrm{MnO_4^-}$, liberate $\mathrm{O_2}$ from water in the presence of an acid?

    • (A)
      No, because $E^\circ_{cell}=-2.733$ V
    • (B)
      Yes, because $E^\circ_{cell}=+0.287$ V
    • (C)
      No, because $E^\circ_{cell}=-0.287$ V
    • (D)
      Yes, because $E^\circ_{cell}=+2.733$ V
11. 11.

    NEET 2022

    Find the EMF of the cell in which the following reaction takes place at 298 K:

    $$\mathrm{Ni(s)+2Ag^+(0.001\,M)\rightarrow Ni^{2+}(0.001\,M)+2Ag(s)}$$

    (Given that $E^\circ_{cell}=1.05$ V, $\dfrac{2.303\,RT}{F}=0.059$ at 298 K)

    • (A)
      1.05 V
    • (B)
      1.0385 V
    • (C)
      1.385 V
    • (D)
      0.9615 V
12. 12.

    NEET 2021

    The molar conductance of NaCl, HCl and $\mathrm{CH_3COONa}$ at infinite dilution are $126.45$, $426.16$ and $91.0\ \mathrm{S\,cm^2\,mol^{-1}}$ respectively. The molar conductance of $\mathrm{CH_3COOH}$ at infinite dilution is. Choose the right option for your answer.

    • (A)
      $540.48\ \mathrm{S\,cm^2\,mol^{-1}}$
    • (B)
      $698.28\ \mathrm{S\,cm^2\,mol^{-1}}$
    • (C)
      $201.28\ \mathrm{S\,cm^2\,mol^{-1}}$
    • (D)
      $390.71\ \mathrm{S\,cm^2\,mol^{-1}}$
13. 13.

    NEET 2021

    The molar conductivity of $0.007\ \mathrm{M}$ acetic acid is $20\ \mathrm{S\,cm^2\,mol^{-1}}$. What is the dissociation constant of acetic acid ? Choose the correct option. $\left[\Lambda^\circ_{\mathrm{H^+}} = 350\ \mathrm{S\,cm^2\,mol^{-1}},\ \Lambda^\circ_{\mathrm{CH_3COO^-}} = 50\ \mathrm{S\,cm^2\,mol^{-1}}\right]$

    • (A)
      $2.50\times10^{-5}\ \mathrm{mol\,L^{-1}}$
    • (B)
      $1.75\times10^{-4}\ \mathrm{mol\,L^{-1}}$
    • (C)
      $2.50\times10^{-4}\ \mathrm{mol\,L^{-1}}$
    • (D)
      $1.75\times10^{-5}\ \mathrm{mol\,L^{-1}}$
14. 14.

    NEET 2020

    On electrolysis of dil. sulphuric acid using Platinum (Pt) electrode, the product obtained at anode will be :

    • (A)
      Hydrogen gas
    • (B)
      Oxygen gas
    • (C)
      $\mathrm{H_2S}$ gas
    • (D)
      $\mathrm{SO_2}$ gas
15. 15.

    NEET 2020

    The number of Faradays (F) required to produce $20$ g of calcium from molten $\mathrm{CaCl_2}$ (Atomic mass of Ca = $40$ g mol$^{-1}$) is :

    • (A)
      1
    • (B)
      2
    • (C)
      3
    • (D)
      4