Question

Define : Standard electrode potential.

Answer 1

Hint: The Standard electrode potential which is represented by $E_{cell}^0$ is the measurement of the potential of a reaction at electrode at standard state of all the quantities like temperature, pressure and concentration etc.

Complete step by step answer:
This term is from electrochemistry.
It may be defined as the potential of the half cell reaction which is measured against the standard hydrogen electrode under the standard conditions. The standard conditions are temperature is 298 K, pressure = 1atm, concentration = 1M. The standard electrode potential is represented by $E_{cell}^0$.
The standard electrode potential of an individual electrode can be measured by pairing it with standard hydrogen electrode thus, making a galvanic cell. After this, the cell potential of the cell is measured.
We know that the electrode potential of Standard hydrogen electrode is 0 Volt. Thus, one can easily get standard electrode potential of a cell.

Additional Information:
We know that all the electrochemical cells are based on the redox reaction. This means that each cell consists of two half cell reactions- the reduction half cell reaction and the oxidation half cell reaction. The oxidation i.e. the gain of electrons take place at anode while the reduction i.e. the loss of electrons take place at cathode. Both the anode and cathode are in separate compartments but are connected by a channel that allows the movement of electrons. Some electric potential arises between the two electrodes due to potential difference between them.

Note: When we require the individual reduction potential of a half cell reaction, then there is a need for standard electrode potential. The Standard hydrogen electrode is used as the reference electrode to measure the standard electrode potential. The value of electrode potential for standard hydrogen electrodes is assumed to be zero always.