Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Electrochemistry question

2022 · 25 Jul · Shift 1 · Q14
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /JEE Main
  3. /Chemistry
  4. /Electrochemistry
  5. /2022 · 25 Jul · Shift 1 · Q14

Electrochemistry question

2022 · 25 Jul · Shift 1 · Q14

JEE MainChemistryElectrochemistryNumerical+4 / −1
The cell potential for Zn∣Zn2+(aq)∣∣Snx+∣Sn\mathrm{Zn}\left|\mathrm{Zn}^{2+}(\mathrm{aq})\right|\left|\mathrm{Sn}^{x+}\right| \mathrm{Sn}Zn​Zn2+(aq)​​Snx+​Sn is 0.801 V0.801 \mathrm{~V}0.801 V at 298 K298 \mathrm{~K}298 K. The reaction quotient for the above reaction is 10−210^{-2}10−2. The number of electrons involved in the given electrochemical cell reaction is ‾\underline{\hspace{2cm}}​. (\left(\right.( Given :EZn2+∣Zno=−0.763 V,ESnx+∣Sno=+0.008 V: \mathrm{E}_{\mathrm{Zn}^{2+} \mid \mathrm{Zn}}^{\mathrm{o}}=-0.763 \mathrm{~V}, \mathrm{E}_{\mathrm{Sn}^{x+} \mid \mathrm{Sn}}^{\mathrm{o}}=+0.008 \mathrm{~V}:EZn2+∣Zno​=−0.763 V,ESnx+∣Sno​=+0.008 V and 2.303RTF=0.06 V)\left.\frac{2.303 \mathrm{RT}}{\mathrm{F}}=0.06 \mathrm{~V}\right)F2.303RT​=0.06 V)
Numerical answer
View written solutionFree

Correct answer: 4

  1. Identify the cell reaction and standard cell potential

The cell is Zn∣Zn2+(aq)∣∣Snx+∣Sn\mathrm{Zn}|\mathrm{Zn}^{2+}(aq)||\mathrm{Sn}^{x+}|\mathrm{Sn}Zn∣Zn2+(aq)∣∣Snx+∣Sn

So, zinc acts as the anode and tin ion acts as the cathode.

Half-reactions:

  • Anode: Zn→Zn2++2e−\mathrm{Zn} \to \mathrm{Zn}^{2+} + 2e^-Zn→Zn2++2e−
  • Cathode: Snx++xe−→Sn\mathrm{Sn}^{x+} + xe^- \to \mathrm{Sn}Snx++xe−→Sn

Given standard reduction potentials: EZn2+/Zn∘=−0.763 VE^\circ_{\mathrm{Zn}^{2+}/\mathrm{Zn}}=-0.763\,\text{V}EZn2+/Zn∘​=−0.763V ESnx+/Sn∘=+0.008 VE^\circ_{\mathrm{Sn}^{x+}/\mathrm{Sn}}=+0.008\,\text{V}ESnx+/Sn∘​=+0.008V

Therefore, Ecell∘=Ecathode∘−Eanode∘E^\circ_{\text{cell}}=E^\circ_{\text{cathode}}-E^\circ_{\text{anode}}Ecell∘​=Ecathode∘​−Eanode∘​ Ecell∘=0.008−(−0.763)=0.771 VE^\circ_{\text{cell}}=0.008-(-0.763)=0.771\,\text{V}Ecell∘​=0.008−(−0.763)=0.771V

  1. Apply the Nernst equation

At 298 K298\,\text{K}298K, Ecell=Ecell∘−0.06nlog⁡QE_{\text{cell}}=E^\circ_{\text{cell}}-\frac{0.06}{n}\log QEcell​=Ecell∘​−n0.06​logQ

Given: Ecell=0.801 V,Q=10−2E_{\text{cell}}=0.801\,\text{V}, \quad Q=10^{-2}Ecell​=0.801V,Q=10−2

Since log⁡(10−2)=−2\log(10^{-2})=-2log(10−2)=−2

So, 0.801=0.771−0.06n(−2)0.801=0.771-\frac{0.06}{n}(-2)0.801=0.771−n0.06​(−2) 0.801=0.771+0.12n0.801=0.771+\frac{0.12}{n}0.801=0.771+n0.12​

  1. Solve for nnn

0.801−0.771=0.12n0.801-0.771=\frac{0.12}{n}0.801−0.771=n0.12​ 0.030=0.12n0.030=\frac{0.12}{n}0.030=n0.12​

Thus, n=0.120.03=4n=\frac{0.12}{0.03}=4n=0.030.12​=4

  1. Final answer

The number of electrons involved in the cell reaction is 4\boxed{4}4​

PreviousNext

More from Electrochemistry

  • The spin-only magnetic moment value of M3+ ion (in gaseous state) from the pairs Cr3+ / Cr2+, Mn3+ / Mn2+, Fe3+ / Fe2+ and Co3+ / Co2+ that has negative standard electrode potential, is ​…2022 · Numerical
  • The molar conductivity of a conductivity cell filled with 10 moles of 20 mL NaCl solution is Λm1​ and that of 20 moles another identical cell heaving 80 mL NaCl solution is Λm2​. The conductivities exhibited by…2022 · MCQ
  • In a cell, the following reactions take place Fe2+→Fe3++e−2I−→I2​+2e−​EFe3+/Fe2+o​=0.77VEI2​/I−o​=0.54V​…2022 · Numerical
  • A solution of Fe2​(SO4​)3​ is electrolyzed for 'x' min with a current of 1.5 A to deposit 0.3482 g of Fe. The value of x is ​. [nearest integer] Given : 1 F = 96500 C mol − 1 Atomic mass of Fe = 56 g mol…2022 · Numerical
  • The correct order of reduction potentials of the following pairs is A. Cl2​/Cl− B. I2​/I− C. Ag+/Ag D. Na+/Na E. Li+/Li Choose the correct answer from the options given below.2022 · MCQ
  • The amount of charge in F(Faraday) required to obtain one mole of iron from Fe3​O4​ is ​. (Nearest Integer)2022 · Numerical
  • The (∂T∂E​)P​ of different types of half cells are as follows: (Where E is the electromotive force) Which of the above half cells would be preferred to be used as reference electrode? Includes table2022 · MCQ
  • Cu(s) + Sn2+ (0.001M) → Cu2+ (0.01M) + Sn(s) The Gibbs free energy change for the above reaction at 298 K is x × 10 − 1 kJ mol − 1. The value of x is ​. [nearest integer] [Given : ECu2+/CuΘ​=0.34V…2022 · Numerical