What will happen when a silver ring is placed in an acidic solution?

What is the oxidation and reduction potential of standard hydrogen electrode?

If in a galvanic cell,the hydrogen half-cell is the anode on the left side,what is the sign of the standard potential of such a galvanic cell? Give an example.

Given are $E^{\circ}$ values for some half reactions:
$I_2 + 2e^{-} \to 2I^{-}$ ; $E^{\circ} = 0.54 \, V$
$MnO_4^{-} + 8H^{+} + 5e^{-} \to Mn^{2+} + 4H_2O$ ; $E^{\circ} = 1.52 \, V$
$Fe^{3+} + e^{-} \to Fe^{2+}$ ; $E^{\circ} = 0.77 \, V$
$Sn^{4+} + 2e^{-} \to Sn^{2+}$ ; $E^{\circ} = 0.1 \, V$
The strongest reducant and oxidant respectively are:

Among $Mg$,$Cu$,$Fe$,and $Zn$,the metal that does not produce hydrogen gas in reaction with hydrochloric acid is:

Will $Fe_{(s)}$ be oxidised to $Fe^{2+}$ by the reaction with $1 \ M$ $HCl$ ($E^o$ for $Fe/Fe^{2+} = +0.44 \ V$)?