We can ensure a constant (if small) supply of Co3+ during our reaction by bubbling air through our
reaction solution, thereby supplying O2 and keeping the above equilibrium lying to the left. We
will also use the stronger oxidizing agent, hydrogen peroxide (H2O2), to oxidize cobalt to Co+3.
Once Co3+ is coordinated by the en and Cl ligands, it is stable against reduction by water back to
Co+2.