JEE Main 202623 JanuaryEvening Shift
- Exam
- JEE Main
- Year
- 2026
- Date
- 23 January
- Shift
- Evening Shift
- Subject
- Chemistry
- Chapter
- Electrochemistry
JEE Main 2026 · 23 January · Evening Shift · Chemistry · Electrochemistry
Consider the above electrochemical cell where a metal electrode (M)...
Consider the above electrochemical cell where a metal electrode (M) is undergoing redox reaction by forming . The cation is present in two different concentrations and as shown above. Which of the following statement is correct for generating a positive cell potential?
Options
- AIf is present at cathode, then .
- BIf is present at anode, then .
- CIf is present at cathode, then .
- DIf is present at anode, then .
Correct answer
C. If is present at cathode, then .
Step-by-step solution
The given setup is a concentration cell with identical electrodes (M) and different electrolyte concentrations ( and ).
For a concentration cell, the standard cell potential .
The cell reactions are:
Anode:
Cathode:
Net reaction:
Using the Nernst equation at :
For a positive cell potential (), the term must be negative.
This requires , which means .
If is present at the cathode and is at the anode, then for , we must have .
Checking the options:
(1) is at cathode, (Incorrect)
(2) is at anode, (Incorrect, would require )
(3) is at cathode, (Correct)
(4) is at anode, (Incorrect, would be zero)
For a concentration cell, the standard cell potential .
The cell reactions are:
Anode:
Cathode:
Net reaction:
Using the Nernst equation at :
For a positive cell potential (), the term must be negative.
This requires , which means .
If is present at the cathode and is at the anode, then for , we must have .
Checking the options:
(1) is at cathode, (Incorrect)
(2) is at anode, (Incorrect, would require )
(3) is at cathode, (Correct)
(4) is at anode, (Incorrect, would be zero)