Electrochemistry · JEE Main previous year questions

2024 15 questions

1. Q622024 · 9 Apr 2024 · Shift 1
   
   1. A.A - weak electrolyte B - weak electrolyte
   2. B.A - weak electrolyte B - strong electrolyte
   3. C.A - strong electrolyte B - strong electrolyte
   4. D.A - strong electrolyte B - weak electrolyte
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   Answer: B

2. Q812024 · 9 Apr 2024 · Shift 1· Numerical answer

   The standard reduction potentials at $298\text{ K}$ for the following half cells are given below : $\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}+14{\mathrm{H}}^{+}+6{\mathrm{e}}^{-}\to 2C{\mathrm{r}}^{3+}+7{\mathrm{H}}_2\mathrm{O},{\mathrm{E}}^{\circ }=1.33\mathrm{V}$ $\mathrm{F}{\mathrm{e}}^{3+}(\mathrm{aq})+3{\mathrm{e}}^{-}\to \mathrm{Fe}{\mathrm{E}}^{\circ }=-0.04\mathrm{V}$ $\mathrm{N}{\mathrm{i}}^{2+}(\mathrm{aq})+2{\mathrm{e}}^{-}\to \mathrm{Ni}{\mathrm{E}}^{\circ }=-0.25\mathrm{V}$ $\mathrm{A}{\mathrm{g}}^{+}(\mathrm{aq})+{\mathrm{e}}^{-}\to \mathrm{Ag}{\mathrm{E}}^{\circ }=0.80\mathrm{V}$ $\mathrm{A}{\mathrm{u}}^{3+}(\mathrm{aq})+3{\mathrm{e}}^{-}\to \mathrm{Au}{\mathrm{E}}^{\circ }=1.40\mathrm{V}$ Consider the given electrochemical reactions, The number of metal(s) which will be oxidized by $\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}$, in aqueous solution is ______.

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   Answer: 3

3. Q692024 · 9 Apr 2024 · Shift 2

   Match List I with List II $$\begin{array}{llll}& \text{LIST I (Cell)}& & \text{LIST II (Use/Property/Reaction)}\\ \text{A.}& \text{Leclanche cell}& \text{I.}& \text{Converts energy of combustion into electrical energy}\\ \text{B.}& \text{Ni - Cd cell}& \text{II.}& \text{Does not involve any ion in solution and is used in hearing aids}\\ \text{C.}& \text{Fuel cell}& \text{III.}& \text{Rechargeable}\\ \text{D.}& \text{Mercury cell}& \text{IV.}& \text{Reaction at anode}\mathrm{Zn}\to \mathrm{Z}{\mathrm{n}}^{2+}+2{\mathrm{e}}^{-}\end{array}$$ Choose the correct answer from the options given below :

   1. A.A-III, B-I, C-IV, D-II
   2. B.A-I, B-II, C-III, D-IV
   3. C.A-IV, B-III, C-I, D-II
   4. D.A-II, B-III, C-IV, D-I
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   Answer: C

4. Q722024 · 9 Apr 2024 · Shift 2

   Which out of the following is a correct equation to show change in molar conductivity with respect to concentration for a weak electrolyte, if the symbols carry their usual meaning :

   1. A.${\Lambda }_{\mathrm{m}}-{\Lambda }_{\mathrm{m}}^{\circ }+{\mathrm{AC}}^{\frac{1}{2}}=0$
   2. B.${\Lambda }_{\mathrm{m}}^2\mathrm{C}+{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{\circ 2}-{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}{\Lambda }_{\mathrm{m}}^{\circ }=0$
   3. C.${\Lambda }_{\mathrm{m}}-{\Lambda }_{\mathrm{m}}^{\circ }-{\mathrm{AC}}^{\frac{1}{2}}=0$
   4. D.${\Lambda }_{\mathrm{m}}^2\mathrm{C}-{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{\circ 2}+{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}{\Lambda }_{\mathrm{m}}^{\circ }=0$
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   Answer: D

5. Q692024 · 8 Apr 2024 · Shift 2

   The reaction; $$\frac{1}{2}{\mathrm{H}}_{2(\mathrm{g})}+{\mathrm{AgCl}}_{(\mathrm{s})}\to {\mathrm{H}}_{(\mathrm{aq})}^{+}+{\mathrm{Cl}}_{(\mathrm{aq})}^{-}+{\mathrm{Ag}}_{(\mathrm{s})}$$ occurs in which of the following galvanic cell :

   1. A.$\mathrm{Pt}\left|{\mathrm{H}}_{2(\mathrm{g})}\right|{\mathrm{HCl}}_{(soln.)}\left|{\mathrm{AgNO}}_{3(\mathrm{aq})}\right|\mathrm{Ag}$
   2. B.$\mathrm{Ag}\left|{\mathrm{AgCl}}_{(\mathrm{s})}\right|{\mathrm{KCl}}_{(soln.)}\left|{\mathrm{AgNO}}_{3(\mathrm{aq})}\right|\mathrm{Ag}$
   3. C.$\mathrm{Pt}\left|{\mathrm{H}}_{2(\mathrm{g})}\right|{\mathrm{KCl}}_{(soln.)}\left|{\mathrm{AgCl}}_{(\mathrm{s})}\right|\mathrm{Ag}$
   4. D.$\mathrm{Pt}\left|{\mathrm{H}}_{2(\mathrm{g})}\right|{\mathrm{HCl}}_{(soln.)}\left|{\mathrm{AgCl}}_{(\mathrm{s})}\right|\mathrm{Ag}$
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   Answer: D

6. Q692024 · 6 Apr 2024 · Shift 2

   How can an electrochemical cell be converted into an electrolytic cell ?

   1. A.Applying an external opposite potential greater than ${\text{E}}_{\text{cell}}^0$
   2. B.Exchanging the electrodes at anode and cathode.
   3. C.Applying an external opposite potential lower than ${\text{E}}_{\text{cell}}^0$
   4. D.Reversing the flow of ions in salt bridge.
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   Answer: A

7. Q792024 · 5 Apr 2024 · Shift 2

   For the electrochemical cell $M|{\mathrm{M}}^{2+}||X|{\mathrm{X}}^{2-}$ If ${\mathrm{E}}_{({\mathrm{M}}^{2+}/M)}^0=0.46\mathrm{V}$ and ${\mathrm{E}}_{(X/{\mathrm{X}}^{2-})}^0=0.34\mathrm{V}$. Which of the following is correct?

   1. A.${\mathrm{E}}_{\mathrm{cell}}=0.80\mathrm{V}$
   2. B.$\mathrm{M}+\mathrm{X}\to {\mathrm{M}}^{2+}+{\mathrm{X}}^{2-}$ is a spontaneous reaction
   3. C.${\mathrm{E}}_{\mathrm{cell}}=-0.80\mathrm{V}$
   4. D.${\mathrm{M}}^{2+}+{\mathrm{X}}^{2-}\to \mathrm{M}+\mathrm{X}$ is a spontaneous reaction
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   Answer: D

8. Q612024 · 4 Apr 2024 · Shift 2

   Fuel cell, using hydrogen and oxygen as fuels, A. has been used in spaceship B. has an efficiency of 40% to produce electricity C. uses aluminum as catalysts D. is eco-friendly E. is actually a type of Galvanic cell only Choose the correct answer from the options given below:

   1. A.A, D, E only
   2. B.A, B, C only
   3. C.A, B, D only
   4. D.A, B, D, E only
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   Answer: A

9. Q692024 · 4 Apr 2024 · Shift 2

   For a strong electrolyte, a plot of molar conductivity against $(\text{concentration}{)}^{1/2}$ is a straight line, with a negative slope, the correct unit for the slope is

   1. A.$\text{S}{\text{cm}}^2{\text{ mol}}^{-3/2}\text{ L}$
   2. B.$\text{S}{\text{cm}}^2{\text{ mol}}^{-3/2}{\text{ L}}^{-1/2}$
   3. C.$\text{S}{\text{cm}}^2{\text{ mol}}^{-1}{\text{ L}}^{1/2}$
   4. D.$\text{S}{\text{cm}}^2{\text{ mol}}^{-3/2}{\text{ L}}^{1/2}$
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   Answer: D

10. Q702024 · 31 Jan 2024 · Shift 1

    Identify the factor from the following that does not affect electrolytic conductance of a solution.

    1. A.The nature of solvent used.
    2. B.The nature of the electrolyte added.
    3. C.The nature of the electrode used.
    4. D.Concentration of the electrolyte.
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    Answer: C

11. Q752024 · 31 Jan 2024 · Shift 1

    The metals that are employed in the battery industries are A. $\mathrm{Fe}$ B. $\mathrm{Mn}$ C. $\mathrm{Ni}$ D. $\mathrm{Cr}$ E. $\mathrm{Cd}$ Choose the correct answer from the options given below:

    1. A.A, B, C, D and E
    2. B.A, B, C and D only
    3. C.B, D and E only
    4. D.B, C and E only
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    Answer: D

12. Q842024 · 31 Jan 2024 · Shift 1· Numerical answer

    Number of alkanes obtained on electrolysis of a mixture of $\mathrm{C}{\mathrm{H}}_3\mathrm{COONa}$ and ${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{COONa}$ is ____.

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    Answer: 3

13. Q852024 · 31 Jan 2024 · Shift 2· Numerical answer

    The values of conductivity of some materials at $298.15\mathrm{K}$ in $\mathrm{S}{\mathrm{m}}^{-1}$ are $2.1\times 10^3$, $1.0\times 10^{-16},1.2\times 10,3.91,1.5\times 10^{-2},1\times 10^{-7},1.0\times 10^3$. The number of conductors among the materials is ____.

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    Answer: 4

14. Q812024 · 29 Jan 2024 · Shift 1· Numerical answer

    The mass of zinc produced by the electrolysis of zinc sulphate solution with a steady current of $0.015\text{ A}$ for 15 minutes is _________ $\times 10^{-4}\text{ g}$. (Atomic mass of zinc $=65.4\text{ amu}$)

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    Answer: 46

15. Q852024 · 29 Jan 2024 · Shift 2· Numerical answer

    A constant current was passed through a solution of $\mathrm{AuC}{\mathrm{l}}_4^{-}$ ion between gold electrodes. After a period of 10.0 minutes, the increase in mass of cathode was $1.314\text{ g}$. The total charge passed through the solution is _________ $\times 10^{-2}\text{ F}$. (Given atomic mass of $\mathrm{Au}=197$)

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    Answer: 2