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# Given are the standard reduction potentials of a some species.The value of $E^{\large\circ}$ will be about

$\begin{array}{1 1}0.44V\\0.54V\\0.65V\\0.76V\end{array}$

We have $[4SO_2+4H^++6e^-\rightarrow S_4O_6^{2-}+2H_2O]\times 2\quad \Delta G_1^{\large\circ}=-12F(0.44V)$
$[S_4O_6^-+2e^-\rightarrow 2S_2O_3^{2-}]\times 2\quad \Delta G_2^{\large\circ}=-4F(0.08V)$
$4S_2O_3^{2-}+24H^++16e^-\rightarrow S_8+12H_2O\quad \Delta G_3^{\large\circ}=-16F(0.47V)$
$SO_2+32H^++32e^-\rightarrow S_8+16H_2O\quad \Delta G_4^{\large\circ}=-32FE^{\large\circ}$
$32E^{\large\circ}=(12\times 0.44+4\times 0.08+16\times 0.47)V$
$E^{\large\circ}=-(14.12/32)V=0.44V$