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Electrochemistry

JEE Main 2024 (Online) 4th April Morning ShiftMCQMedium📈 Topic in 29% papers+4−1
Ques. 1JEE Main 2024, 4 April (Morning Shift)

What pressure (bar) of H2 would be required to make emf of hydrogen electrode zero in pure water at 25 ?

  1. 0.5
  2. 10-14
  3. 1
  4. 10-7

Answer

(2) 10-14

Solution

2H+(aq) + 2e- H2(g), E = 0

Nernst: E = E - 0.0592 PH2[H+]2

E = 0 ⇒ PH2[H+]2 = 0 ⇒ PH2 = [H+]2

∵ pure water at 25 : [H+] = 10-7 M

⇒ PH2 = (10-7)2 = 10-14 bar

Answer: (2)

Note: The official NTA answer key gives option (3). Our faculty team has re-checked this question and finds option (2) correct, as explained above.

Keep practising — Electrochemistry

Ques. 2JEE Main 2024, 4 April (Evening Shift)

Fuel cell, using hydrogen and oxygen as fuels, Choose the correct answer from the options given below:

  1. A, D, E only
  2. A, B, C only
  3. A, B, D only
  4. A, B, D, E only
Ques. 3JEE Main 2024, 4 April (Evening Shift)

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

  1. S cm2 mol-3/2 L
  2. S cm2 mol-3/2 L-1/2
  3. S cm2 mol-1 L1/2
  4. S cm2 mol-3/2 L1/2
Ques. 4JEE Main 2024, 1 February (Morning Shift)

The potential for the given half cell at 298 K is (-) 10-2 V 2H+(aq) + 2e- H2(g) [H+] = 1 M, PH2 = 2 atm (Given : 2.303 RT/F = 0.06 V, 2 = 0.3)

Ques. 5JEE Main 2024, 1 February (Evening Shift)

The amount of electricity in Coulomb required for the oxidation of 1 mol of H2O to O2 is 105 C.

Ques. 6JEE Main 2024, 1 February (Evening Shift)

Consider the following redox reaction : MnO4- + H+ + H2C2O4 Mn2+ + H2O + CO2 The standard reduction potentials are given as below ( E0red ) : E MnO4-/Mn2+ = +1.51 V E CO2/H2C2O4 = -0.49 V If the equilibrium constant of the above reaction is given as Keq = 10x, then the value of x = (nearest integer)

Ques. 7JEE Main 2024, 31 January (Morning Shift)

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

  1. The nature of solvent used.
  2. The nature of the electrolyte added.
  3. The nature of the electrode used.
  4. Concentration of the electrolyte.
Ques. 8JEE Main 2024, 31 January (Morning Shift)

One Faraday of electricity liberates x 10-1 gram atom of copper from copper sulphate. x is .

Ques. 9JEE Main 2024, 31 January (Evening Shift)

The values of conductivity of some materials at 298.15 K in S m-1 are 2.1 103, 1.0 10-16, 1.2 10, 3.91, 1.5 10-2, 1 10-7, 1.0 103. The number of conductors among the materials is .

Ques. 10JEE Main 2024, 30 January (Evening Shift)

Reduction potential of ions are given below: [figure] The correct order of their oxidising power is :

  1. IO4- > BrO4- > ClO4-
  2. BrO4- > ClO4- > IO4-
  3. ClO4- > IO4- > BrO4-
  4. BrO4- > IO4- > ClO4-
Ques. 11JEE Main 2024, 29 January (Morning Shift)

The mass of zinc produced by the electrolysis of zinc sulphate solution with a steady current of 0.015 A for 15 minutes is 10-4 g. (Atomic mass of zinc = 65.4 amu)

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