What is the reduction potential of a hydrogen gas electrode when pure hydrogen gas is at $1 \ atm$ pressure and the platinum electrode is in contact with an $HCl$ solution of $pH$ $1$ at $298 \ K$ (in $V$)?

The change in electrode potential of $Cr^{3+}/Cr_2O_7^{2-}$ electrode at $25 \ ^oC$ due to change in $pH$ of its electrolytic solution from $1$ to $3$ is ........... $V$ (Assume: $[Cr_2O_7^{2-}]$ and $[Cr^{3+}]$ remain constant). Use: $\frac{2.303RT}{F} = 0.06$.

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?

The potential of a hydrogen electrode at $pH = 10$ is (in $V$)

Consider the electrochemical cell: $Pt \ | \ O_{2(g)} \ (1 \ bar) \ | \ HCl \ (aq) \ || \ M^{2+} \ (aq, 1.0 \ M) \ | \ M_{(s)}$. The pH above which,oxygen gas would start to evolve at the anode is . . . . . . (nearest integer). $\left[ \text{Given :} \ E^{\circ}_{M^{2+}/M} = 0.994 \ V, \ E^{\circ}_{O_{2}/H_{2}O} = 1.23 \ V, \ \frac{RT}{F}(2.303) = 0.059 \ V \ \text{at the given condition} \right]$

The equilibrium constant of the reaction $Cu_{(s)} + 2Ag^{+}_{(aq)} \to Cu^{2+}_{(aq)} + 2Ag_{(s)}$ with $E^{\circ} = 0.46 \ V$ at $298 \ K$ is approximately: