Preparation of redox electrode such as fe2+ fe3+ pt and measurement of its potential using calomel electrode and determination of electrode potential by changing concentration of fe2+ and fe3+ ions
Answers
As Pt wire is dipped in aqueous solution that contains ferrous and ferric ions with an anion specifically counter anion that preserves electroneutrality.
Fe3+ + e- (metal) -------------> Fe2+
If equilibrium lies to left side, it will favor the synthesis of ferric ion. An electrode potential will be established on Pt wire in relation to solution. The relationship of redox system and electrode potential can be explained by Nernst equation.
Electrode potential is determined by comparing it with some reference electrode. There are various reference electrodes which are as follows:
- SHE
- CRE
- AgCl Reference Electrode
The S.C.E. is a common reference electrode.The cell half-reaction is: ½Hg2Cl2 + e- = Hg + Cl-
E = Eo–0.0592 log 1/aCl-= 0.242 V for saturated KCl.
The potential of SCE is +0.242 V.