Which method can be used to find out the strength of reductant/oxidant in a solution? Explain with an example.
Strength of a reductant (reducing agent) or oxidant (oxidising agent) can be found out by measuring the relative electrode potential when it’s connected in a solution using a cell.
For example, Fe3+/Fe is the element we want to test with the Standard Hydrogen electrode (SHE). The half-cell reaction for Fe and H are given below.
H+ + e- → H2 E° = 0.0V
Fe3+ + e- → Fe2+ E° = 0.77V
When any element needs to be evaluated it is placed as an electrode with SHE. The amount of emf it generates in the cell can be considered as the potential of the element.
E°cell = 0-0.77
E°cell = 0.77
The above-assumed configuration of Fe being anode can be reversed and hence strength Fe as a reductant can be established. Hence the strength of an oxidant can be determined.