Q. If E°(Fe²⁺/Fe) = −0.441 V and E°(Fe³⁺/Fe²⁺) = 0.771 V, the standard emf of the reaction : Fe + 2Fe³⁺ → 3Fe²⁺ will be :
A) 0.441 V
B) 1.753 V
C) 1.212 V
D) 0.211 V
Explanation
[Solution from source] Fe is oxidised to Fe²⁺ (anode) and Fe³⁺ is reduced to Fe²⁺ (cathode). E°cell = E°cathode − E°anode = 0.771 − (−0.441) = 1.212 V. Electrode potentials are intensive, so they are not multiplied by 2; simply adding them gives the wrong 0.33 V. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.