For a cell having a standard $emf$ of $0.295 \ V$ at $25^o \ C$ involving a two-electron change,the equilibrium constant for the reaction is:

Which Nernst equation is correct for the following cell? $Al_{(s)}|Al_{(aq)}^{3+} || Zn_{(aq)}^{2+}| Zn_{(s)}$

At $298 \ K$,a $1 \ L$ solution containing $10 \ mmol$ of $Cr_2O_7^{2-}$ and $100 \ mmol$ of $Cr^{3+}$ shows a $pH$ of $3.0$. Given: $Cr_2O_7^{2-} \rightarrow Cr^{3+}; E^0 = 1.330 \ V$ and $\frac{2.303 RT}{F} = 0.059 \ V$. The potential for the half-cell reaction is $x \times 10^{-3} \ V$. The value of $x$ is $........$

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

The concentration of potassium ions inside a biological cell is at least twenty times higher than the outside. The resulting potential difference across the cell is important in several processes such as transmission of nerve impulses and maintaining the ion balance. $A$ simple model for such a concentration cell involving a metal $M$ is:
$M_{(s)} \mid M^{+}(aq; 0.05 \ M) \parallel M^{+}(aq; 1 \ M) \mid M_{(s)}$
For the above electrolytic cell the magnitude of the cell potential $|E_{cell}|=70 \ mV$.
$1.$ For the above cell
$(A)$ $E_{cell} < 0 ; \Delta G > 0$ $(B)$ $E_{cell} > 0 ; \Delta G < 0$
$(C)$ $E_{cell} < 0 ; \Delta G^{\circ} > 0$ $(D)$ $E_{cell} > 0 ; \Delta G^{\circ} > 0$
$2.$ If the $0.05 \ M$ solution of $M^{+}$ is replaced by $0.0025 \ M$ $M^{+}$ solution,then the magnitude of the cell potential would be
$(A)$ $35 \ mV$ $(B)$ $70 \ mV$ $(C)$ $140 \ mV$ $(D)$ $700 \ mV$
Give the answer for questions $1$ and $2$.

If $E^{\circ}(Cu^{2+}_{(aq)} \mid Cu_{(s)}) = +0.34 \ V$. What is the potential for $Cu_{(s)} \rightarrow Cu^{2+}_{(aq)} (0.1 \ M) + 2e^-$ at $298 \ K$?