The $emf$ of the following cell $Mg|Mg^{2+}(0.01 \ M)||Sn^{2+}(0.1 \ M)|Sn$ at $298 \ K$ in $V$ is: (Given: $E^{\circ}_{Mg^{2+}|Mg} = -2.34 \ V, E^{\circ}_{Sn^{2+}|Sn} = -0.14 \ V$)

$Zn_{(s)} + Cl_2(1 \ atm) \to Zn^{2+} + 2Cl^-$. The $E^0_{cell}$ of the cell is $2.12 \ V$. To increase $E_{cell}$:

The $E^o$ for the cell $Zn|Zn^{2+}_{(aq)}||Cu^{2+}_{(aq)}|Cu$ is $1.10 \ V$ at $25 \ ^oC$. The equilibrium constant for the reaction $Zn + Cu^{2+}_{(aq)} \rightleftharpoons Cu + Zn^{2+}_{(aq)}$ is of the order of:

The $emf$ of a $Daniell$ cell at $298 \, K$ is $E_1$:
$Zn | ZnSO_4 \,(0.01 \, M) || CuSO_4 \,(1.0 \, M) | Cu$
When the concentration of $ZnSO_4$ is $1.0 \, M$ and that of $CuSO_4$ is $0.01 \, M$,the $emf$ changes to $E_2$. What is the relation between $E_1$ and $E_2$?

$A$ solution containing $4.5 \ mM$ of $MnO_4^{-}$ and $15 \ mM$ of $Mn^{2+}$ shows $pH$ of $2$. The potential of the half-cell reaction is $......$. (Given: $\log 15 = 1.176$,$\log 4.5 = 0.653$,and standard potential of $MnO_4^{-} \longrightarrow Mn^{2+}$ is $1.51 \ V$) (in $V$)

Consider the electrochemical cell shown in the figure where a metal electrode $(M)$ undergoes a redox reaction by forming $M^{+}$ $(M \rightarrow M^{+} + e^{-})$. The cation $M^{+}$ is present in two different concentrations $c_{1}$ and $c_{2}$. Which of the following statements is correct for generating a positive cell potential?