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Electrochemistry · Question 12

NEET (UG) 2022MCQEasy📈 Topic in 12% papers+4−1
1

At 298 K, the standard electrode potentials of Cu2+/Cu, Zn2+/Zn, Fe2+/Fe and 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?

  1. CuSO4(aq) + Zn(s) ZnSO4(aq) + Cu(s)
  2. CuSO4(aq) + Fe(s) FeSO4(aq) + Cu(s)
  3. FeSO4(aq) + Zn(s) ZnSO4(aq) + Fe(s)
  4. 2CuSO4(aq) + 2Ag(s) 2Cu(s) + Ag2SO4(aq)

Answer

(4) 2CuSO4(aq) + 2Ag(s) 2Cu(s) + Ag2SO4(aq)

Solution

A metal with lower (more negative) E displaces the metal ion of higher E from its solution, i.e. E cell = E cathode - E anode > 0.

(1) E cell = 0.34 - (-0.76) = +1.10 V ⇒ occurs.

(2) E cell = 0.34 - (-0.44) = +0.78 V ⇒ occurs.

(3) E cell = -0.44 - (-0.76) = +0.32 V ⇒ occurs.

(4) E cell = 0.34 - 0.80 = -0.46 V ⇒ negative, so Ag cannot reduce Cu2+; the reaction cannot occur.

Answer: (4)

NEET (UG) 2022

Keep practising — Electrochemistry

2

Given below are half cell reactions: MnO4- + 8H+ + 5e- Mn2+ + 4H2O, E Mn2+/MnO4- = -1.510 V 12O2 + 2H+ + 2e- H2O E O2/H2O = +1.223 V Will the permanganate ion, MnO4- liberate O2 from water in the presence of an acid?

  1. Yes, because E cell = +0.287 V
  2. No, because E cell = -0.287 V
  3. Yes, because E cell = +2.733 V
  4. No, because E cell = -2.733 V
NEET (UG) 2022
3

Find the emf of the cell in which the following reaction takes place at 298 K Ni(s) + 2Ag+ (0.001 M) Ni2+ (0.001 M) + 2Ag(s) (Given that E cell = 1.05 V, 2.303 RTF = 0.059 at 298 K)

  1. 1.0385 V
  2. 1.385 V
  3. 0.9615 V
  4. 1.05 V
NEET (UG) 2022
4

Two half cell reactions are given below. Co3+ + e- Co2+, E0 Co2+/Co3+ = -1.81 V 2Al3+ + 6e- 2Al(s), E0 Al/Al3+ = +1.66 V The standard EMF of a cell with feasible redox reaction will be :

  1. -3.47 V
  2. +7.09 V
  3. +0.15 V
  4. +3.47 V
NEET (UG) 2022 (Phase 2)
5

Standard electrode potential for the cell with cell reaction Zn(s) + Cu2+(aq) Zn2+(aq) + Cu(s) is 1.1 V. Calculate the standard Gibbs energy change for the cell reaction. (Given F = 96487 C mol-1)

  1. -200.27 J mol-1
  2. -200.27 kJ mol-1
  3. -212.27 kJ mol-1
  4. -212.27 J mol-1
NEET (UG) 2022 (Phase 2)
6

The molar conductance of NaCl, HCl and CH3COONa at infinite dilution are 126.45, 426.16 and 91.0 S cm2 mol-1 respectively. The molar conductance of CH3COOH at infinite dilution is. Choose the right option for your answer.

  1. 540.48 S cm2 mol-1
  2. 201.28 S cm2 mol-1
  3. 390.71 S cm2 mol-1
  4. 698.28 S cm2 mol-1
NEET (UG) 2021
7

The molar conductivity of 0.007 M acetic acid is 20 S cm2 mol-1. What is the dissociation constant of acetic acid? Choose the correct option. [ H+ = 350 S cm2 mol-1 CH3COO- = 50 S cm2 mol-1]

  1. 2.50 10-5 mol L-1
  2. 1.75 10-4 mol L-1
  3. 2.50 10-4 mol L-1
  4. 1.75 10-5 mol L-1
NEET (UG) 2021
8

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

  1. Oxygen gas
  2. H2S gas
  3. SO2 gas
  4. Hydrogen gas
NEET (UG) 2020
9

The number of Faradays(F) required to produce 20 g of calcium from molten CaCl2 (Atomic mass of Ca = 40 g mol-1) is :

  1. 2
  2. 3
  3. 4
  4. 1
NEET (UG) 2020
10

For a cell involving one electron E cell = 0.59 V at 298 K, the equilibrium constant for the cell reaction is : [Given that 2.303 RTF = 0.059 V at T = 298 K]

  1. 1.0 1030
  2. 1.0 1010
  3. 1.0 102
  4. 1.0 105
NEET (UG) 2019
11

For the cell reaction 2Fe3+(aq) + 2I-(aq) 2Fe2+(aq) + I2(aq) E cell = 0.24 V at 298 K. The standard Gibbs energy ( r G ) of the cell reaction is : [Given that Faraday constant F = 96500 C mol-1]

  1. 46.32 kJ mol-1
  2. 23.16 kJ mol-1
  3. -46.32 kJ mol-1
  4. -23.16 kJ mol-1
NEET (UG) 2019

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