Question

(i) Name the two mechanisms by which electron transfer reactions can occur and
explain how they differ.

(ii)Explain how the following reaction was used to deduce the mechanism of inner sphere electron transfer.

[Co(NH3)5Cl]2+ + [Cr(H2O)6]2+ + 5H2O = [Co(H2O)6]2+ + [Cr(H2O)5Cl]2+ + 5NH3

Answer 1

a) The two mechanisms we have are , Inner sphere electron transfer and Outer sphere electron transfer.Electron Transfer reactions are basically redox reactions in which an electron is transferred from one atom or molecule to a similar chemical species and is further accompanied by a change in oxidation states of both the reactant and the product. The basic difference between Inner sphere and Outer sphere electron transfer is that, in an inner sphere electron transfer, the two redox centres are covalently linked by an external bridge.Whereas in outer sphere electron transfer, the redox centres aren.t linked by any bridge.

b) This reaction is a very famous and a lot common example of an Inner sphere electron transfer reaction. Here   the chloride ligand is the bridging ligand/agent that covalently connects the redox partners/centres.