Exams › JEE Main › Chemistry

For the electrochemical reaction 2Fe(s) + O2(g) + 4H+(aq) → 2Fe2+(aq) + 2H2O(l), with E° = 1.67 V, what is the cell potential at 25°C when [Fe2+] = 10−3 M, p(O2) = 0.1 atm, and pH = 3?

1. 1.47 V
2. 1.77 V
3. 1.87 V
4. 1.57 V

Correct answer: 1.77 V

Solution

The correct option is 1.77 V because the Nernst equation accounts for the concentrations of the reactants and products, adjusting the standard cell potential (E°) based on the given conditions, which results in a higher potential than the standard value.

Related JEE Main Chemistry questions

• Which of the following sequences lists the given metals in decreasing order of their standard electrode potentials: Mg, K, Ba and Ca?
• During electrolysis of an aqueous solution of dipotassium succinate, which gas is evolved at the electrodes?
• Which expression gives the equivalent conductance at infinite dilution of Al2(SO4)3, if 9b°Al3+ and 9b°SO4^2− denote the equivalent conductances at infinite dilution of the corresponding ions?
• A weak monobasic acid has an equivalent conductance of 8.0 mho cm^2 for an M/32 solution, while its limiting equivalent conductance at infinite dilution is 400 mho cm^2. What is the dissociation constant of the acid?
• The standard emf of a Daniell cell is 1.10 V. What is the greatest amount of electrical work that can be extracted from this cell?
• During the recharging of a lead storage battery, which reaction takes place at the cathode?

⚔️ Practice JEE Main Chemistry free + battle 1v1 →