Titrations

• In redox titrations, one species is reduced and another is oxidised. In redox titrations, indicators are not always needed.
• Examples of redox titrations include those involving: Manganate (VII), ethanedioate and dichromate (VI) ions.
• A purple standard solution of potassium manganate, KMnO4, is added to the burette and using a pipette, a measured volume of the solution under analysis is added to a conical flask along with excess Sulphuric acid to provide H+ ions. The titration is then carried out.
• Potassium manganate, KMnO4, is added from the burette and oxidises the solution under analysis. e.g. ( Fe2+ -> Fe3+ ). During this, MnO4- ions are reduced to Mn2+, losing their purple colour. Once all of the chemical under analysis has been oxidised, the next drop of MnO4 will remain purple.