Question

Based on the data, arrange fe2+, mn2+ and cr2+ in the increasing order of stability of +2 oxidation state. Ecr3+/cr2+ = 0.4 v emn3+/mn2+ = + 1.5 v efe3+/fe2+ = + 0.8 v

Answer 1

Cr 3+ {Fe3+ {Mn3+
!Based on their emf

Answer 2

Hey dear,

● Answer -
Cr2+ < Fe2+ < Mn2+

● Explanation -
- E° value for redox couple M3+/M2+ gives us idea about stability of its oxidation states.
- More negative E°(M3+/M2+) means more stable +2 oxidation state.

# Observing E°(M3+/M2+) values of ions, we can arrange metals with increasing order of +2 OS stability -
Cr2+ < Fe2+ < Mn2+


Hope this helps you...