The standard electrode potentials of two half-cells are given as: $Ni^{2+}_{(aq)} + 2e^{-} \rightarrow Ni_{(s)}$; $E^o = -0.25 \ V$ and $Zn^{2+}_{(aq)} + 2e^{-} \rightarrow Zn_{(s)}$; $E^o = -0.76 \ V$. What is the standard $emf$ of the cell formed by connecting these two half-cells in $volt$?

Consider the following reduction processes:
$Al^{3+} + 3e^{-} \rightarrow Al_{(s)}, E^{\circ} = -1.66 \ V$
$Fe^{3+} + e^{-} \rightarrow Fe^{2+}, E^{\circ} = +0.77 \ V$
$Co^{3+} + e^{-} \rightarrow Co^{2+}, E^{\circ} = +1.81 \ V$
$Cr^{3+} + 3e^{-} \rightarrow Cr_{(s)}, E^{\circ} = -0.74 \ V$
The tendency to act as a reducing agent decreases in the order:

The $E^{\circ}$ for Daniell cell is $1.1 \ V$. Calculate $\Delta G^{\circ}$ for the following reaction: $Zn_{(s)} + Cu^{2+}_{(aq)} \rightleftharpoons Zn^{2+}_{(aq)} + Cu_{(s)}$

What is denoted by a negative $E^o$ and a positive $E^o$ value in electrochemistry?

The $(\frac{\partial E}{\partial T})_P$ of different types of half cells are as follows:

$A$	$B$	$C$	$D$
$1 \times 10^{-4}$	$2 \times 10^{-4}$	$0.1 \times 10^{-4}$	$0.2 \times 10^{-4}$

(Where $E$ is the electromotive force)
Which of the above half cells would be preferred to be used as reference electrode?

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.
$(iv)$ $E_{cell}^o = -\frac{\Delta_r G^o}{nF}$