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Electrochemistry

JEE Main 2025 (Online) 23rd January Morning ShiftMCQMedium📈 Topic in 13% papers+4−1
Ques. 1JEE Main 2025, 23 January (Morning Shift)

FeO42- +2.0 V Fe3+ 0.8 V Fe2+ -0.5 V Fe0 In the above diagram, the standard electrode potentials are given in volts (over the arrow). The value of E (FeO42-/Fe2+) is :

  1. 1.2 V
  2. 2.1 V
  3. 1.4 V
  4. 1.7 V

Answer

(4) 1.7 V

Solution

Concept: E is not additive, but G = -nFE is.

FeO42- Fe3+: n1 = 3, E = 2.0 V

Fe3+ Fe2+: n2 = 1, E = 0.8 V

-4FE = -3F(2.0) - 1F(0.8) ⇒ E = 6.84 = 1.7 V

Answer: (4)

Keep practising — Electrochemistry

Ques. 2JEE Main 2025, 23 January (Evening Shift)

Standard electrode potentials for a few half cells are mentioned below : E Cu2+/Cu = 0.34 V, E Zn2+/Zn = -0.76 V E Ag+/Ag = 0.80 V, E Mg2+/Mg = -2.37 V Which one of the following cells gives the most negative value of G ?

  1. Zn | Zn2+(1M) || Ag+(1M) | Ag
  2. Ag | Ag+(1M) || Mg2+(1M) | Mg
  3. Zn | Zn2+(1M) || Mg2+(1M) | Mg
  4. Cu | Cu2+(1M) || Ag+(1M) | Ag
Ques. 3JEE Main 2025, 22 January (Morning Shift)

Which of the following electrolyte can be used to obtain H2S2O8 by the process of electrolysis ?

  1. Concentrated solution of sulphuric acid
  2. Dilute solution of sodium sulphate.
  3. Acidified dilute solution of sodium sulphate.
  4. Dilute solution of sulphuric acid
Ques. 4JEE Main 2025, 22 January (Morning Shift)

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A. The amount of the aluminium deposited at the cathode is . [Given : molar mass of aluminium and chlorine are 27 g mol-1 and 35.5 g mol-1 respectively. Faraday constant = 96500 C mol-1]

  1. 1.660 g
  2. 1.007 g
  3. 0.336 g
  4. 0.441 g
Ques. 5JEE Main 2025, 22 January (Evening Shift)

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true

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