On the basis of standard electrode potential values,suggest which of the following reactions would take place?

For a saturated solution of $Ag_{2}CrO_{4}$ at infinite dilution,$\lambda_{m}^{\infty}(Ag^{+}) = 127 \ \Omega^{-1} \ cm^{2} \ mol^{-1}$ and $\lambda_{m}^{\infty}(CrO_{4}^{2-}) = 246 \ \Omega^{-1} \ cm^{2} \ mol^{-1}$. If the specific conductance of the solution is $2 \times 10^{-2} \ \Omega^{-1} \ cm^{-1}$,calculate the solubility product $(K_{sp})$ of $Ag_{2}CrO_{4}$.

Given that $Ni^{2+}/Ni = -0.25 \ V$; $Cu^{2+}/Cu = 0.34 \ V$; $Ag^{+}/Ag = 0.80 \ V$; $Zn^{2+}/Zn = -0.76 \ V$. Which of the following reactions under standard conditions will not take place in the specified direction?

Given $E_{Fe^{3+}/Fe^{2+}}^{\circ} = +0.76 \ V$ and $E_{I_{2}/I^{-}}^{\circ} = +0.55 \ V$. The equilibrium constant for the reaction taking place in a galvanic cell consisting of the above two electrodes is (Given $\frac{2.303 \ RT}{F} = 0.06 \ V$)

Copper from copper sulphate solution can be displaced by .............. The standard reduction potentials of some electrodes are given below:
$E^o (Fe^{2+}, Fe) = -0.44 \ V$
$E^o (Zn^{2+}, Zn) = -0.76 \ V$
$E^o (Cu^{2+}, Cu) = +0.34 \ V$
$E^o (Cr^{2+}, Cr) = -0.74 \ V$
$E^o (H^{+}, 1/2H_2) = 0.00 \ V$

The process of rusting of iron occurs as follows:
$Fe \rightarrow Fe^{2+} + 2e^{-}, E^{o} = 0.44 \ V$
$2H^{+} + 2e^{-} + \frac{1}{2} O_2 \rightarrow H_2O_{(l)}, E^{o} = 1.23 \ V$
Then for this reaction,$\Delta G^{o} = .... \ kJ/mol$