Electrochemistry – JEE Main Previous Year Questions with Solutions

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JEE Main Previous Year Papers Questions of Chemistry with Solutions are available at eSaral. Practicing JEE Main chapter wise questions of Chemistry will help the JEE aspirants in realizing the question pattern as well as help in analyzing weak & strong areas.

 

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Previous Years AIEEE/JEE Mains Questions

Q. Given :

$\mathrm{E}_{\mathrm{Fe}^{-3} / \mathrm{Fe}}^{\circ}=-0.036 \mathrm{V}, \quad \mathrm{E}_{\mathrm{Fe}^{-2} / \mathrm{Fe}}^{\circ}=-0.439 \mathrm{V}$. The value of standard electrode potential for the change.

$\mathrm{Fe}^{+3}_{(\mathrm{aq})}+\mathrm{e}^{-} \longrightarrow \mathrm{Fe}^{+2}_{(\mathrm{aq})}$ will be :-

(1) 0.770 V (2) –0.27 V (3) –0.072 V (4) 0.385 V

AIEEE 2009

Sol. (1)

$\mathrm{E}^{\circ}=\frac{3 \times-0.036+2 \times 0.439}{1}=0.77 \Rightarrow \mathrm{A}$


Q. The Gibbs energy for the decomposition of $\mathrm{Al}_{2} \mathrm{O}_{3}$ at $500^{\circ} \mathrm{C}$ is as follows :

$\frac{2}{3} \mathrm{Al}_{2} \mathrm{O}_{3} \longrightarrow \frac{4}{3} \mathrm{Al}+\mathrm{O}_{2}, \mathrm{AG}=+966 \mathrm{KJ} \mathrm{mol}^{-1}$ The potential difference needed for electrolytic reduction of $\mathrm{Al}_{2} \mathrm{O}_{3}$ at $500^{\circ} \mathrm{C}$ is at least :-

(1) 5.0 V      (2) 4.5 V       (3) 3.0 V         (4) 2.5 V

AIEEE 2010

Sol. (4)

$966 \times 10^{3}=4 \times 96500 \times \mathrm{E} \Rightarrow \mathrm{E}=2.5 \mathrm{V}$


Q. Resistance of 0.2 M solution of an electrolyte is $50 \Omega$. The specific conductance of the solution is 1.3 S $\mathrm{m}^{-1}$. If resistance of the 0.4M solution of the same electrolyte is $260 \Omega$, its molar conductivity is :-

(1) $6250 \mathrm{Sm}^{2} \mathrm{mol}^{-1}$

(2) $6.25 \times 10^{-4} \mathrm{S} \mathrm{m}^{2} \mathrm{mol}^{-1}$

(3) $625 \times 10^{-4} \mathrm{S} \mathrm{m}^{2} \mathrm{mol}^{-1}$

(4) $62.5 \mathrm{S} \mathrm{m}^{2} \mathrm{mol}^{-1}$

AIEEE 2011/JEE-MAIN 2014

Sol. (2)


Q. The reduction potential of hydrogen half-cell will be negative if :-

(1) $\mathrm{p}\left(\mathrm{H}_{2}\right)=2 \operatorname{atm}\left[\mathrm{H}^{+}\right]=1.0 \mathrm{M}$

(2) $\mathrm{p}\left(\mathrm{H}_{2}\right)=2$ atm and $\left[\mathrm{H}^{+}\right]=2.0 \mathrm{M}$

(3) $\mathrm{p}\left(\mathrm{H}_{2}\right)=1$ atm and $\left[\mathrm{H}^{+}\right]=2.0 \mathrm{M}$

(4) $\mathrm{p}\left(\mathrm{H}_{2}\right)=1$ atm and $\left[\mathrm{H}^{+}\right]=1.0 \mathrm{M}$

AIEEE 2011

Sol. (1)


Q. The standard reduction potentials for $\mathrm{Zn}^{2+} / \mathrm{Zn}, \mathrm{Ni}^{2+} / \mathrm{Ni}$ and $\mathrm{Fe}^{2+} / \mathrm{Fe}$ are $-0.76,-0.23$ and – 0.44 V respectively. The reaction $\mathrm{X}+\mathrm{Y}^{+2} \rightarrow \mathrm{X}^{2+}+\mathrm{Y}$ will be spontaneous when

(1) X = Zn, Y = Ni

(2) X = Ni, Y = Fe

(3) X = Ni, Y = Zn

(4) X = Fe, Y = Zn

Sol. (1)

For spontaneous reaction $\mathrm{E}^{\circ}>0 \mathrm{so}(\mathrm{A})$


Q. Given :

Based on the data given above, strongest oxidising agent will be :

(1) Cl–

(2) $\mathrm{Cr}^{3+}$

(3) $\mathrm{Mn}^{2+}$

(4) $\mathrm{MnO}_{4}^{-}$

JEE-Mains 2013

Sol. (4)

Higher the SRP, stronger will be oxidising agent

Hence, $\mathrm{MnO}_{4}^{-}$ is stronger oxidising agent.


Q. The equivalent conductance of NaCl at concentration C and at infinite dilution are $\lambda_{\mathrm{C}}$ and $\lambda_{\infty}$ , respectively. The correct relationship between $\lambda_{\mathrm{C}}$ and $\lambda_{\infty}$ is given as:

(1) $\lambda_{\mathrm{C}}=\lambda_{\infty}-(\mathrm{B}) \sqrt{\mathrm{C}}$

(2) $\lambda_{\mathrm{C}}=\lambda_{\infty}+(\mathrm{B}) \sqrt{\mathrm{C}}$

(3) $\lambda_{\mathrm{C}}=\lambda_{\infty}+(\mathrm{B}) \mathrm{C}$

(4) $\lambda_{\mathrm{C}}=\lambda_{\infty}-(\mathrm{B}) \mathrm{C}$

JEE-Mains 2014

Sol. (1)

Fact


Q. At 298 K, the standard reduction potentials are 1.51 V for $\mathrm{MnO}_{4}-| \mathrm{Mn}^{2+}$ , 1.36 V for $\mathrm{Cl}_{2} | \mathrm{Cl}^{-}$, 1.07 V for $\mathrm{Br}_{2} | \mathrm{Br}^{-},$ and $0.54 \mathrm{V}$ for $\mathrm{I}_{2} | \mathrm{I}^{-} .$ At $\mathrm{pH}=3$, permanganate is expected to oxidize $\left(\frac{\mathrm{RT}}{\mathrm{F}}=0.059 \mathrm{V}\right):-$

(1) $\mathrm{Cl}^{-}$ and $\mathrm{Br}^{-}$

(2) $\mathrm{Cl}^{-}, \mathrm{Br}^{-}$ and $\mathrm{I}^{-}$

(3) $\mathrm{Br}^{-}$ and $\mathrm{I}^{-}$

(4) I- only

JEE-Mains (online) 2015

Sol. (3)


Q. A variable, opposite external potential $\left(\mathrm{E}_{\mathrm{ext}}\right)$ is applied to the cell

$\mathrm{Zn}\left|\mathrm{Zn}^{2+}(1 \mathrm{M}) \| \mathrm{Cu}^{2+}(1 \mathrm{M})\right| \mathrm{Cu}$, of potential 1.1 V. When $\mathrm{E}_{\mathrm{ext}}<1.1 \mathrm{V}$ and $\mathrm{E}_{\mathrm{ext}}>1.1 \mathrm{V}$ , respectively electrons flow from :

(1) anode to cathode in both cases

(2) anode to cathode and cathode to anode

(3) cathode to anode in both cases

(4) cathode to anode and anode to cathode

JEE-Mains (online) 2015

Sol. (2)

Fact


Q. Two Faraday of electricity is passed through a solution of $\mathrm{CuSO}_{4}$. The mass of copper deposited at the cathode is :

(at. mass of Cu = 63.5 amu)

(1) 2g         (2) 127 g          (3) 0 g          (4) 63.5 g

JEE-Mains 2015

Sol. (4)

$2 \mathrm{F}=2 \mathrm{eq}=1$ mole $=63.5 \mathrm{gm}$


Q. Galvanization is applying a coating of :-

(1)Zn         (2) Pb         (3) Cr        (4) Cu

JEE-Mains 2016

Sol. (1)

Galvanization is the process of applying a protective zinc coating of steel or iron, to prevent rusting.


Q. Given

(1)Cr

(2) $\mathrm{Mn}^{2+}$

(3) $\mathrm{Cr}^{3+}$

(4) $\mathrm{Cl}^{-}$

JEE-Mains 2017

Sol. (1)

Since $\mathrm{Cr}^{+3}$ is having least reducing potential, so Cr is the best Reducing agent.


Q. How long (approximate) should water be electrolysed by passing through 100

amperes current so that the oxygen released can completely burn 27.66 g of diborane ?

(Atomic weight of B = 10.8 u)

(1)0.8 hours

(2) 3.2 hours

(3) 1.6 hours

(4) 6.4 hours

JEE-Mains 2018

Sol. (2)


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Comments
  • September 12, 2020 at 2:29 pm

    Need detailed solutions

  • August 30, 2020 at 8:03 pm

    Thanks

  • August 28, 2020 at 3:58 pm

    plz make it better

  • August 22, 2020 at 4:35 pm

    Please add questions of 2019 and 2020 as well

  • August 20, 2020 at 8:19 pm

    Still more questions are required plz add questions of 2019 and 20 questions in it…. And also provide detail solutions

  • August 16, 2020 at 10:55 pm

    Sir , I want to purchase previous years IIT JEE Chapter wise. Chemistry Questions with solution, you have any book for this pl confirm & cost of book

  • August 3, 2020 at 6:52 pm

    Helpful

  • July 15, 2020 at 3:45 pm

    Plz bro questions are dope but i need clr solutions even i cant solve it

  • July 2, 2020 at 7:54 pm

    clear solutions required

  • June 22, 2020 at 7:44 am

    Clear solutions required

  • June 22, 2020 at 7:44 am

    Clear solutions required

  • Pg
    June 21, 2020 at 2:32 pm

    Need more questions for practice

  • June 18, 2020 at 11:29 am

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  • May 31, 2020 at 3:12 pm

    Can u provide clear solutions

  • May 22, 2020 at 6:55 pm

    Chill bro

  • May 9, 2020 at 11:01 pm

    Excellent

  • March 23, 2020 at 6:43 am

    Very nice

  • March 23, 2020 at 6:42 am

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