Redox titration is a type of chemical titration in which a redox reaction takes place. It is a method of quantifying the amount of oxidizing or reducing agent in a given sample by measuring the amount of reagent needed to fully react with it. The term “redox” comes from the words “reduction” and “oxidation”, which refer to the transfer of electrons between species in a chemical reaction.
In a redox titration, a solution containing the oxidizing or reducing agent is titrated with a solution of the other species. For example, if we want to determine the amount of iron (II) ions in a solution, we can titrate it with a solution of potassium permanganate, which acts as an oxidizing agent. Iron (II) ions will be oxidized to iron (III) ions, while the permanganate ions will be reduced to manganese (II) ions.
The end-point of a redox titration is determined by monitoring a change in color or potential. In the above example, the end-point is reached when all the iron (II) ions have been oxidized to iron (III) ions, which will cause the solution to turn from green to purple due to the presence of excess permanganate ions.
Redox titrations can be performed using a variety of redox indicators, such as potassium permanganate, potassium dichromate, and iodine. The choice of indicator depends on the particular redox reaction being studied.
Redox titrations have many practical applications, including the analysis of metals, the determination of the purity of chemical compounds, and the measurement of the concentration of certain biological molecules. They are commonly used in analytical chemistry, biochemistry, and environmental chemistry.