NTA Abhyas NEET2020ChemistryElectrochemistryPractice
From the given standard electrode potentials of two half cells F e + + + 2 e - → F e ; E o = - 0.440 V F e + + + + 3 e - → F e ; E o = - 0.036 V Calculate the standard electrode potential ( E o ) for F e + + + + e - → F e + + is
Options
- A+ 0.772 V
- B– 0.404 V
- C+ 0.404 V
- D– 0.476 V
Correct answer
A. + 0.772 V
Step-by-step solution
Δ G o = - n E o F F e 2 + + 2 e - → F e …..(i) Δ G o = - 2 × F × ( - 0.440 V ) = 0.880 F F e 3 + + 3 e - → F e …..(ii) Δ G o = - 3 × F × ( - 0.036 ) = 0.108 F On subtracting equation (i) from (ii) F e 3 + + e - → F e 2 + Δ G o = 0.108 F - 0.880 F = - 0.772 F E o for the reaction = - Δ G o n F = - ( - 0.772 F ) 1 × F = + 0.772 V