The standard e.m.f. of a cell,involving one electron change,is found to be $0.591 \ V$ at $25 \ ^oC$. The equilibrium constant of the reaction is: $(F = 96,500 \ C \ mol^{-1}; R = 8.314 \ J \ K^{-1} \ mol^{-1})$

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

Calculate the e.m.f. of the half-cell given below: $Fe | FeSO_4$ $(a = 0.1 \ M)$ where $E^o_{OP} = 0.44 \ V$. (in $V$)

The logarithm of the equilibrium constant for the reaction $Pd^{2+}{(aq)} + 4Cl^{-}{(aq)} \rightleftharpoons PdCl_4^{2-}{(aq)}$ is (Nearest integer).
Given: $\frac{2.303 RT}{F} = 0.06 \ V$
$Pd^{2+}{(aq)} + 2e^{-} \rightleftharpoons Pd_{(s)} \quad E^{\circ} = 0.83 \ V$
$PdCl_4^{2-}{(aq)} + 2e^{-} \rightleftharpoons Pd_{(s)} + 4Cl^{-}{(aq)} \quad E^{\circ} = 0.65 \ V$

What is the sign of $\Delta G^o$ and the value of $K$ for an electrochemical cell for which $E_{cell}^o = 0.80 \ V$?

By how much would the oxidising power of the $(MnO_4^- / Mn^{2+})$ couple change if the $H^{+}$ ion concentration is increased up to $100$ times at $25 ^oC$?