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Electrochemistry

JEE Main 2025 (Online) 29th January Morning ShiftMCQEasy📈 Topic in 21% papers+4−1
Ques. 1JEE Main 2025, 29 January (Morning Shift)

The molar conductivity of a weak electrolyte when plotted against the square root of its concentration, which of the following is expected to be observed?

  1. Molar conductivity increases sharply with increase in concentration.
  2. Molar conductivity decreases sharply with increase in concentration.
  3. A small increase in molar conductivity is observed at infinite dilution.
  4. A small decrease in molar conductivity is observed at infinite dilution.

Answer

(2) Molar conductivity decreases sharply with increase in concentration.

Solution

As per NCERT, for a weak electrolyte (e.g. CH3COOH) m = m .

On dilution the degree of dissociation increases steeply, so m rises sharply at low concentration.

Conversely, m decreases sharply as the concentration increases; the plot of m vs c is a steep curve, not a straight line (unlike a strong electrolyte, where m decreases only slightly and linearly).

Answer: (2)

Keep practising — Electrochemistry

Ques. 2JEE Main 2025, 29 January (Evening Shift)

Match List - I with List - II : Choose the correct answer from the options given below :

  1. (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
  2. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
  3. (A)-(IV), (B)-(III), (C)-(II), (D)-(I)
  4. (A)-(III), (B)-(II), (C)-(IV), (D)-(I)
Ques. 3JEE Main 2025, 29 January (Evening Shift)

O2 gas will be evolved as a product of electrolysis of : Choose the correct answer from the options given below :

  1. (B) and (C) only
  2. (B) and (D) only
  3. (A) and (D) only
  4. (A) and (C) only
Ques. 4JEE Main 2025, 28 January (Morning Shift)

Given below is the plot of the molar conductivity vs concentration for KCl in aqueous solution. [figure] If, for the higher concentration of KCl solution, the resistance of the conductivity cell is 100 , then the resistance of the same cell with the dilute solution is 'x' . The value of x is (Nearest integer)

Ques. 5JEE Main 2025, 28 January (Evening Shift)

Electrolysis of 600 mL aqueous solution of NaCl for 5 min changes the pH of the solution to 12. The current in Amperes used for the given electrolysis is . (Nearest integer).

Ques. 6JEE Main 2025, 24 January (Morning Shift)

For the given cell Fe2+(aq) + Ag+(aq) Fe3+(aq) + Ag(s) The standard cell potential of the above reaction is Given: Ag+ + e- Ag E = xV Fe2+ + 2e- Fe E = yV Fe3+ + 3e- Fe E = zV

  1. x + 2y - 3z
  2. x + 2y
  3. y - 2x
  4. x + y - z
Ques. 7JEE Main 2025, 24 January (Evening Shift)

Based on the data given below : E (Cr2O72-/Cr3+)=1.33 V E (Cl2/Cl-)=1.36 V E (MnO4-/Mn2+)=1.51 V E (Cr3+/Cr)=-0.74 V the strongest reducing agent is :

  1. Cl-
  2. MnO4-
  3. Cr
  4. Mn2+
Ques. 8JEE 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
Ques. 9JEE 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. 10JEE 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. 11JEE 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

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