Uses of Standard Electrode Potential Chemistry Notes
Uses of Standard Electrode Potential :
There are following uses of standard electrode potential:
→ Reducing and Oxidising Power – The electrode whose value of standard reduction potential is more, also have more tendency to be reduced. So, it is strong oxidising agent. Whereas, the electrode whose value of standard reduction potential is less, also have low tendency to be reduced. So, it is strong reducing agent.
→ Oxidising power ∝ Standard Reduction Potential Hence, Li is strongest reducing agent and fluorine is strongest oxidising agent.
→ Replacement of Hydrogen from Acids by Metals-The metals, whose value of standard reduction potential is less than standard reduction potential of hydrogen, are strong reducing agent than hydrogen. So, these can replace hydrogen from dilute acids. For example, Zinc can replace hydrogen from dilute acid but Cu, Ag, Au do not.
Zn + 2H+ → Zn2+ + H2
→ Displacement of Metal from their Solution-The metals, whose value of standard reduction potential is less, can displace those metals from their solution whose values of standard reduction potentials are more. For example, Zn metal can displace Cu metal from CuSO4 solution whereas Cu metal does not displace Zn from ZnSO4 solution.
Zn + CuSO4 → ZnSO4 + Cu
But Cu + ZnSO4 → No reaction
→ Reduction of Metal Oxides by Hydrogen-The oxides of such metals, whose value of standard reduction potential is more than hydrogen, are reduced by hydrogen. For example: The reduction of CuO is possible by hydrogen while reduction of Feo is not possible.
→ Possibility of Reaction-The redox reactions or cell reactions whose value of electromotive force or value of E° are positive, are spontaneous reactions.
Fe + Ni2+ → Fe2+ + Ni
In above reaction,
The value of coll is positive. So, reaction is possible in forward direction.
Since the value of E°cell is negative. So, the reaction is not possible in forward direction but it is possible in reverse direction.