Upon dipping a copper rod into an aqueous solution of the salt,the solution that turns blue is

At $298 \ K$ temperature,if $E^o_{Mg^{2+}|Mg} = -2.37 \ V$ and $E^o_{Co^{2+}|Co} = -0.28 \ V$,construct a galvanic cell and provide its symbolic representation.

When a $Cu$ rod is kept in an $AgNO_3$ solution,what is the redox reaction that occurs?

An electrochemical cell is set up as follows: $Pt(H_2, 1 \, atm) | 0.1 \, M \, HCl || 0.1 \, M \, CH_3COOH | (H_2, 1 \, atm) Pt$. The $E.M.F.$ of this cell will not be zero because:

For the reaction $2 Fe^{3+}_{(aq)} + 2 I^{-}_{(aq)} \rightarrow 2 Fe^{2+}_{(aq)} + I_{2(s)}$,the magnitude of the standard molar free energy change,$\Delta_{r} G_{m}^{\circ} = -$ ........... $kJ$ (Round off to the Nearest Integer). $\left[ E_{Fe^{2+} / Fe_{(s)}}^{\circ} = -0.440 \ V; \ E_{Fe^{3+} / Fe_{(s)}}^{\circ} = -0.036 \ V; \ E_{I_{2} / 2I^{-}}^{\circ} = 0.539 \ V; \ F = 96500 \ C \ mol^{-1} \right]$

For a hydrogen-oxygen fuel cell at $1 \text{ atm}$ and $298 \text{ K}$, the reaction is $H_{2(g)} + \frac{1}{2} O_{2(g)} \rightarrow H_{2}O_{(l)}$; $\Delta G^{\circ} = -240 \text{ kJ}$. The $E^{\circ}$ for the cell is approximately (Given $F = 96,500 \text{ C}$): (in $\text{ V}$)