Standard half-cell potential E° : If the ionic species have concentration of mol dm–3and pressure of the gaseous species is 1 atm (101.325 KPa), than half-cell potential is called as standard half-cell potential. The temperature being 298 K.
Absolute value of half-cell potential cannot be determined experimentally. However, its value relative to reference electrode can be determined.
Reference electrode 11 given half-cell. E°cell can be measured experimentally using a potentiometer.
Knowing the standard reduction potential of the reference electrode E°half-cell can be found out.
= 1.05 V – 0.0295 x log 80
= 1.05 V – 0.0295 x 1.9031
= 1.05 V – 0.056 = 0.99 V.