Question

Can a metal in a complex ion undergo a redox reaction?

Answer 1

Yes, the metal in a complex ion can undergo reduction-oxidation reaction.

Explanation:

An example is the oxidation of `"Co"^"2+"` to `"Co"^"3+"` by hydrogen peroxide.

If you add an excess of `"NH"_3` to a solution of `"Co"^"2+"` ions, you get the hexaamminecobalt(II) ion, `"Co"("NH"_3)_6^"2+"`.

This is oxidized rapidly by hydrogen peroxide to the hexaamminecobalt(III) ion, `"Co"("NH"_3)_6^"3+"`.

The equation for the reaction is

`underbrace("2Co"("NH"_3)_6^"2+")_color(red)("yellow-brown") + "H"_2"O"_2 → underbrace("2Co"("NH"_3)_6^"3+")_color(red)("deep orange-brown") + "2HO"^"-"`