A redox couple is defined as having together the oxidized and reduced forms of a substance taking part in an oxidation or reduction half reaction . Represented as Zn 2 +/ Zn and Cu 2 + / Cu .
Electrochemical cells are the devices which are used to get electric current by using chemical reaction .
The potential associated with each electrode is known as electrode potential . If the concentration of each species taking part in the electrode reaction is unity ( if any gas appears in the electrode reaction , it is confined to 1 atmospheric pressure ) and further the reaction is carried out at 298K , then the potential of each electrode is said to be the Standard Electrode Potential .
SHE is used to measure electrode potential and its standard electrode potential is taken as 0.00 V .