Calculate $\frac{?}{{?}_{\frac{?}{?}}{?}_{r}G}$ and the equilibrium constant for the following reactions at $298K.$

a$.,Z{n}^{2+}(aq)+Sn(s)Zn(s)+S{n}^{2+}(aq)$

You may need to use the following data:

$Z{n}^{2+}(aq)+2e^{-}Zn(s),E=-0\mathrm{.}763V$

$S{n}^{2+}(aq)+2e^{-}Sn(s),E=-0\mathrm{.}14V\frac{?}{{?}_{\frac{?}{?}}{?}_r}$

$G=,kJ$

kJ

Equilibrium constant $=$

b$.,Cu(s)+2A{g}^{+}(aq)C{u}^{2+}(aq)+2Ag(s)$

You may need to use the following data:

$A{g}^{+}(aq)+e^{-}Ag(s),E=+0\mathrm{.}799V$

$C{u}^{2+}(aq)+2e^{-}Cu(s),E=+0\mathrm{.}337V\frac{?}{{?}_{\frac{?}{?}}{?}_r}$

$GkJ$

Equilibrium constant $=$