The $EMF$ of a hydrogen electrode in terms of $pH$ is (at $1 \ atm$ pressure).

Identify the correct statement$(s)$:

The $EMF$ of the following three galvanic cells are $E_1, E_2$ and $E_3$ respectively. Which of the following is correct?
$(i)$ $Zn | Zn^{2+} (1 \ M) || Cu^{2+} (0.1 \ M) | Cu$
$(ii)$ $Zn | Zn^{2+} (1 \ M) || Cu^{2+} (1 \ M) | Cu$
$(iii)$ $Zn | Zn^{2+} (0.1 \ M) || Cu^{2+} (1 \ M) | Cu$

What will be the electrode potential of $Cu$ electrode dipped in $0.025 \ M$ $CuSO_4$ solution at $298 \ K$? Given that the standard reduction potential of $Cu^{2+}/Cu$ is $0.34 \ V$.

$E^0 = \frac{RT}{nF} \ln K_{eq}$. This is called

Calculate the cell potential for $Cr_{(s)} | Cr^{3+} (0.1 \, M) || Fe^{2+} (0.01 \, M) | Fe_{(s)}$ at $298 \, K$. Given $E^{\circ}_{Cr^{3+}/Cr} = -0.74 \, V$ and $E^{\circ}_{Fe^{2+}/Fe} = -0.44 \, V$. (in $, V$)