Potentiometric Titrations

• PRINCIPLE : Potential of an electrode depends upon the concentration to which it is reversible in accordance with Nernst Equation. In Pot. Titr., the change in electrode potential upon addition of titrant is noted. The vol of titrant added is plotted against emf. At end point, rate of change of potential is maximum
• Redox reactions can be followed by using an inert indicator electrode, a bright platinum wire or foil
• Titration involves transfer of electrons from the substance being oxidized to the substance being reduced
• End point of a redox reaction can be determined by potentiometric titration
• PROCEDURE: 20mL FeSO4 sol'n added to a beaker followed by 20mL H2SO4 sol'n to make it acidic medium. Pt electrode is inserted into this sol'n and it is couple with SCE. Potential difference between electrodes measured using digital voltmeter. Std ceric ammonium sulphate is taken in burette added to beaker in 1mL instalments and EMF is noted from voltmeter for each addition and is plotted against the vol of ceric sol'n. Titration is repeated more precisely near end point by adding 0.1mL each