Question

Fe3+ + e- --> Fe2+ is called a___________ ___________ because two (one for oxidation, one for reduction) are normally required to represent a complete chemical process.

Answer 1

Fe3+ + e- --> Fe2+ is called a redox pair because two (one for oxidation, one for reduction) are normally required to represent a complete chemical process.

In this reaction, the reduction of Fe³⁺ by accepting 1e depends on the presence of Fe²⁺. In reverse direction, Fe²⁺ gets oxidized by releasing 1e.

Or,        Fe³⁺ + 1e ------> Fe²⁺

            Fe²⁺ - 1e -------> Fe³⁺

Since, the conversion of Fe³⁺ into Fe²⁺ and vice versa depends on each other, they form a redox pair. Such redox pairs are central to electron transport chains and several biochemical pathways as they provide the means of energy conversion/ transfer in from of excited electrons.