At equilibrium,which of the following conditions is satisfied?

If a strip of $Cu$ metal is placed in a solution of ferrous sulphate,what will happen?

The standard reduction potentials at $298 \ K$ for the following half-cells are given below:
$Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$,$E^{\circ} = 1.33 \ V$
$Fe^{3+} + 3e^- \rightarrow Fe$,$E^{\circ} = -0.04 \ V$
$Ni^{2+} + 2e^- \rightarrow Ni$,$E^{\circ} = -0.25 \ V$
$Ag^+ + e^- \rightarrow Ag$,$E^{\circ} = 0.80 \ V$
$Au^{3+} + 3e^- \rightarrow Au$,$E^{\circ} = 1.40 \ V$
Consider the given electrochemical reactions. The number of metal$(s)$ which will be oxidized by $Cr_2O_7^{2-}$ in aqueous solution is $.....$

Given $\lambda^{\circ}_{Mg^{2+}} = 106 \ S \ cm^2 \ mole^{-1}$ and $\lambda^{\circ}_{SO_4^{2-}} = 160 \ S \ cm^2 \ mole^{-1}$. The value of $\lambda^{\circ}_{MgSO_4}$ (in $S \ cm^2 \ mole^{-1}$) is

Which of the following is not used to construct a salt bridge?

If less than $1.1 \ V$ external opposite current is passed through the Daniell cell,for such condition answer the following questions :
$(1)$ Which are anode and cathode ?
$(2)$ Give direction for electron and current flow.