A common example of a redox titration is treating a solution of iodine with a reducing agent to produce iodide using a starch indicator to help detect the endpoint. Iodine (I2) can be reduced to iodide (I−) by e.g. thiosulfate (S2O32−), and when all iodine is spent the blue colour disappears.

Indicator used in redox titration is Methylene blue.

Explanation:
Redox titration involves the transfer of electrons between the reactants. In order to determine the endpoint of titration, an indicator is used. An indicator is a substance that changes its color depending on the pH or the presence of a particular ion.

Methylene blue is a redox indicator that is commonly used in titrations involving oxidizing and reducing agents. It is a blue-colored dye that gets reduced to a colorless compound when it is in the presence of a reducing agent. The reduction of methylene blue involves the transfer of electrons from the reducing agent to the methylene blue molecule.

During titration, a small amount of methylene blue is added to the solution being titrated. As the titrant is added, the reducing agent in the solution reacts with the titrant and gets oxidized. As the reducing agent gets consumed, the concentration of methylene blue increases in the solution. At the endpoint of titration, the last trace of reducing agent gets consumed and the methylene blue gets completely oxidized to its blue-colored form.

Thus, the color change from colorless to blue indicates the endpoint of the titration. Methylene blue is commonly used in titrations involving iron, tin, and vanadium.