Redox Titrations
- Redox titration is a volumetric method of analysis which relies on oxidation or reduction of the analyte.
- Redox titrations involve the titration of an oxidizing agent with a reducing agent, and vice versa.
- An oxidizing agent gains electrons
- A reducing agent loses electrons
- A half-reaction is obtained by considering the change in oxidation states of individual substances involved in the redox reaction.
- A half-reaction does not occur by itself, at least 2 reactions must be coupled so that the electron released by one electron is accepted by another.
- Therefore oxidation and reduction reactions must take place simultaneously. This is called redox reaction.
- An oxidizing agent and reducing agent which appear on opposite sides of a half-equation constitute a redox couple.
- For every oxidizing agent there is a corresponding reducing agent, and every reducing agent a corresponding oxidizing agent.
- Redox couples are analogous to conjugate acid-base pairs and behave in the same way.
- The stronger an oxidizing agent, the weaker the corresponding reducing agent.
- The stronger the reducing agent, the weaker the corresponding oxidizing agent.
The redox titrations based on redox reactions can be expressed by the equation:
- Changing property of the solution is its redox potential. There must be a sufficiently large difference between the oxidizing and reducing capabilities of the reactants for the reaction to go to completion and give a sharp end point.
- One should be a strong oxidizing agent and the other, a strong reducing agent.