In the cell, Pt(s)| H _ 2 (g,...

$A: \dfrac{1}{2}{H}_{2}\left(g\right) \to {H}^{+}\left(aq .\right) + {e}^{-}; {E}^{o} = 0 .0 V$
$C: AgCl\left(s\right) + {e}^{-} \to Ag\left(s\right) + {Cl}^{-}; {E}^{o} = xV$
${E}_{cell} = {E}_{cell}^{o} - \dfrac{0 .06}{1}\log \left\{\left[{H}^{+}\right]\left[{Cl}^{-}\right]\right\}$
$0 .92 = x - \dfrac{0 . 06}{1}\log \left({10}^{- 12}\right)$
$0 .92 = x + 0 . 72$
$x = 0 .92 - 0 .72$
$= 0 . 2V$