Redox reaction play a pivotal role in chemistry and biology. The values of standard redox…

Redox reaction play a pivotal role in chemistry and biology. The values of standard redox potential (Eº) of two half-cell reactions decide which way the reaction is expected to proceed. A simple example is a Daniell cell in which zinc goes into solution and copper gets deposited. Given below are a set of half-cell reactions (acidic medium) along with their Eº (V with respect to normal hydrogen electrode) values. (2007)
I₂ + 2e^–→ 2Ι^– Eº = 0.54
Cl₂ + 2e^– → 2Cl^– Eº = 1.36
Mn³⁺ + e^– → Mn²⁺ Eº = 1.50
Fe³⁺ + e^– → Fe²⁺ Eº = 0.77
O₂ + 4H⁺ + 4e^– → 2H₂O Eº = 1.23
While Fe³⁺ is stable, Mn³⁺ is not stable in acid solution because