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Electrochemistry

JEE Main 2024 (Online) 5th April Morning ShiftMCQEasy📈 Topic in 14% papers+4−1
Ques. 1JEE Main 2024, 5 April (Morning Shift)

The reaction at cathode in the cells commonly used in clocks involves.

  1. oxidation of Mn from +2 to +7
  2. reduction of Mn from +4 to +3
  3. oxidation of Mn from +3 to +4
  4. reduction of Mn from +7 to +2

Answer

(2) reduction of Mn from +4 to +3

Solution

Clocks use the dry cell (Leclanché cell): anode Zn, cathode carbon rod in MnO2 + C paste

Cathode: +4MnO2 + NH4+ + e- +3MnO(OH) + NH3

∵ Mn gains one electron at the cathode ⇒ reduction from +4 to +3

Answer: (2)

Keep practising — Electrochemistry

Ques. 2JEE Main 2024, 5 April (Evening Shift)

The quantity of silver deposited when one coulomb charge is passed through AgNO3 solution :

  1. 0.1 g atom of silver
  2. 1 chemical equivalent of silver
  3. 1 g of silver
  4. 1 electrochemical equivalent of silver
Ques. 3JEE Main 2024, 5 April (Evening Shift)

For the electrochemical cell M | M2+ || X | X2- If E0(M2+/M) = 0.46 V and E0(X/X2-) = 0.34 V. Which of the following is correct?

  1. Ecell = 0.80 V
  2. M + X M2+ + X2- is a spontaneous reaction
  3. Ecell = -0.80 V
  4. M2+ + X2- M + X is a spontaneous reaction
Ques. 4JEE Main 2024, 4 April (Morning Shift)

One of the commonly used electrode is calomel electrode. Under which of the following categories, calomel electrode comes?

  1. Metal ion - Metal electrodes
  2. Oxidation - Reduction electrodes
  3. Metal - Insoluble Salt - Anion electrodes
  4. Gas - Ion electrodes
Ques. 5JEE 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
Ques. 6JEE 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. 7JEE 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. 8JEE 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. 9JEE 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. 10JEE 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. 11JEE 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.

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