When does the potential of the electrochemical cell become zero?

Options

A. `E_("OX")` of anode and `E_("red")` of cathode become equal
B. `E_("red")^(0)` of anode and `E_("red")^(0)` of cathode become equal
C. `E_("red")` of anode and `E_("red")` of cathode become equal
D. Concentration of both the half cell become same

Answer

C

Explanation

When the opposing potential becomes equal to electrical potential, the cell as a reference electrode whose electrode potential is taken to be zero.