Standard electrode potential is defined as the potential of each electrode if the concentration of each taking part in reaction is unity at 1 atmospheric and 298K temperature. Importance of standard electrode potential in chemical reactions :
1. The reduction potential of lithium is minimum. It has highest capacity to lose electrons, hence, it is the strongest reducing agent. Whereas the reduction potential of fluoride is higher, it as higher capacity to accept electrons and thus strongest oxidising agent.
2. More negative the value of standard electrode potential of metal, more active will be the metal and a good reducing agent. This is the reason when a more active metal is placed in a solution of less active metal, it displaces the less active metal from the solution.
3. The metal in the top of activity series are good reducing agents therefore, their cations cannot be reduced by chemical metals. This is the reason why alkali metals, alkaline earth metals and aluminum etc. are obtained by electrolytic reduction method. The value of E° will be negative.
4. The metals placed above the hydrogen in activity series reduces hydrogen ion into hydrogen. This is why metals react with acids and liberate hydrogen gas.
Zn + 2H+ → Zn2+ + H2
Mg + 2H+ → Mg2+ + H2
5. Any non-metal displace the anion of the non-metal placed above it in the series from its solution.
Cl2 + 2Br– → 2Cl– + Br2
6. The element present below in the series have more capacity to accept electrons as compared to lose electrons. They are good oxidising agents. For example, their cations oxidised H2 to H+ions
2Au+ + 3H2 → 2Au + 6H+
7. Gold and Silver can be precipitated from their salt solutions by the metals more electronegative like zinc, aluminum etc.
2Na[Ag(CN2)]+ Zn → Na2[Zn(CN)4] + 2Ag ↓
