During the preparation of ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8$ (per disulphuric acid) ${\mathrm{O}}_2$ gas also releases at anode as byproduct. When $9.72 \mathrm{L}$ of ${\mathrm{H}}_2$ releases at cathode and $2.35 \mathrm{L}$ ${\mathrm{O}}_2$ at anode at $\mathrm{STP}$, the weight of ${\mathrm{H}}_2{\mathrm{S}}_2{\mathrm{O}}_8$ produced in gram is:

Using the standard potential values given below, decide which of the statements $\mathrm{I}, \mathrm{II}, \mathrm{III}, \mathrm{IV}$ are correct. Choose the right answer from $\left(\mathrm{a}\right),\left(\mathrm{b}\right),\left(\mathrm{c}\right)$ and $\left(\mathrm{d}\right)$

${\mathrm{Fe}}^{2+}+2{\mathrm{e}}^{-}=\mathrm{Fe}, \mathrm{E}°=-0.44 \mathrm{V}$

${\mathrm{Cu}}^{2+}+2{\mathrm{e}}^{-}=\mathrm{Cu}, {\mathrm{E}}^{\mathrm{o}}=+0.34 \mathrm{V}$

${\mathrm{Ag}}^{+}+{\mathrm{e}}^{-}=\mathrm{Ag}, {\mathrm{E}}^{\mathrm{o}}=+0.80 \mathrm{V}$

$\mathrm{I}$. Copper can displace iron from ${\mathrm{FeSO}}_4$ solution

$\mathrm{II}$. Iron can displace copper from ${\mathrm{CuSO}}_4$ solution

$\mathrm{III}$. Silver can displace $\mathrm{Cu}$ from ${\mathrm{CuSO}}_4$ solution

$\mathrm{IV}$. Iron can displace silver from ${\mathrm{AgNO}}_3$ solution