If E°(Fe2+/Fe) is x1 and E°(Fe3+/Fe) is x2 then find E°(Fe3+/Fe2+)
2. The attempt at a solution
We need E for Fe3+ + e ----> Fe2+.
We are given Fe2+ + 2e----->Fe is x1. Reversing will give Fe--->Fe2+ + 2e (-x1)...(i)
also, Fe3+ + 3e----->Fe is x2, ...(ii)
multiply (ii) by 2 and (i) by 3, then adding we have
Fe + 2Fe3+---->3Fe2+ as 2x2-3x1. What now?