Question

Explain why Cr²⁺ is strongly reducing while Mn³⁺ is strongly oxidizing.

Answer 1

Cr²⁺ is strong reducing while Mn³⁺ is strongly oxidising.

`"E"_("Cr"^(3+)//"Cr"^(2+))^0` is −0.41 V

\[\ce{Cr^2+ + 2e^- -> Cr}\]

E⁰ = – 0.91 V

If the standard electrode potential E⁰ of metal is large and negative, the metal is a powerful reducing agent because it loses electrons easily.

\[\ce{Mn -> Mn^3+ + 3e^-}\]

\[\ce{Mn^3+ + e^- -> Mn^2+}\]

Mn³⁺ [Ar] 3d⁴

E⁰ = + 1.51 V

If the standard electrode potential E⁰ of metal is large and positive, the metal is a powerful oxidising agent because it gains electrons easily.