Determine true $(T)$ and false $(F)$ for the following statements:
$(i)$ Always $E_{cell}^o = E_{cell}$
$(ii)$ In standard conditions,$E_{cell}^o = E_{cell}$
$(iii)$ $E_{cell}^o = E_{cell}$ is reached when the cell attains equilibrium.
$(iv)$ $E_{cell}^o = -\frac{\Delta_r G^o}{nF}$

(F, T, F, F) $(i)$ False: $E_{cell}$ depends on the concentration of ions and temperature,whereas $E_{cell}^o$ is a constant for a given cell at $298 \ K$.
$(ii)$ True: Under standard conditions (concentration $= 1 \ M$,pressure $= 1 \ bar$,temperature $= 298 \ K$),the cell potential $E_{cell}$ is equal to the standard cell potential $E_{cell}^o$.
$(iii)$ False: When a cell attains equilibrium,$E_{cell} = 0$,not $E_{cell} = E_{cell}^o$.
$(iv)$ False: The correct relationship is $\Delta_r G^o = -nFE_{cell}^o$,which implies $E_{cell}^o = -\frac{\Delta_r G^o}{nF}$.