To find the standard potential of M3+/M electrode, the following cell is constituted:
The emf of the cell is found to be 0.421 volt at 298 K. The standard potential of half reaction M3++3e−→M at 298 K will be:
(Given EAg+/Ag∘ at 298 K = 0.80 Volt)
(1) 0.66 Volt
(2) 0.32 Volt
(3) 1.28 Volt
(4) 0.38 Volt