Sir/mam, please explain what does a more -ve Edegree value mean? Does it mean that half cell reaction will be carried out on the cathod or the anode? Also How can I identify which one is going under oxidation and whic one under reduction?
It is very confusing while solving problems based on free energy and emf of cell.

Asked by vidyuti.varma | 6th Jul, 2016, 05:36: PM

Expert Answer:

1. The electrode at which reduction takes place with respect to standard hydrogen electrode has reduction potenial which is given a positive sign, the electrode at which oxidation takes place with respect to standard hydrogen electrode has a postive oxidation potential or if expressed as reduction potential, it will have a negative sign. 
2. In the electrochemical series, positive sign is used to represent the reduction potential. It implies that greater the reduction potential, more easily is the substace (element or ion) reduced or in other words, stroger oxidising agent it is.
3. F2 has the highest reduction potential and Li+ ion has the lowest reduction potential, this means that F2 is reduced most easily whereas Li+ ions are reduced with greatest difficulty. In other words, F2 is the strongest oxidising agent whereas Li+ ions are the weakest oxidising agents. 
4. Reduction occurs at te electrode having higher reduction potential. Oxidation occurs at the electrode having lower reduction potential (or higher oxidation potential).
5. Oxidation potential of any electrode = - Reduction potential of the same electrode.

Answered by Prachi Sawant | 7th Jul, 2016, 10:50: AM

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