Chemistry - Redox Reactions Question with Solution | TestHub

The standard reduction potentials of the above species in acidic medium are as given below
${\mathrm{S}}_2{\mathrm{O}}_8^{2-}\left(\mathrm{a}\mathrm{q}\right)+2{\mathrm{e}}^{-}\to 2\mathrm{S}{\mathrm{O}}_4^{2-}\left(\mathrm{a}\mathrm{q}\right);\mathrm{E}°=+2.01\text{V}$
$\mathrm{M}\mathrm{n}{\mathrm{O}}_4^{-}\left(\mathrm{a}\mathrm{q}\right)+8{\mathrm{H}}^{+}+5{\mathrm{e}}^{-}\to \mathrm{M}{\mathrm{n}}^{2+}\left(\mathrm{a}\mathrm{q}\right)+4{\mathrm{H}}_2\mathrm{O};\mathrm{E}°=+1.77\text{V}$
$\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}\left(\mathrm{a}\mathrm{q}\right)+14{\mathrm{H}}^{+}+6{\mathrm{e}}^{-}\to 2\mathrm{C}{\mathrm{r}}^{3+}+7{\mathrm{H}}_2\mathrm{O};\mathrm{E}°=+1.33\text{V}$
The more the standard reduction potential, the more the tendency of the species to undergo reduction and more strongly it (species) would work as oxidizing agent.
As a result, their strength as oxidizing agent in acidic solution decreases in the following order
${\mathrm{S}}_2{\mathrm{O}}_8^{2-}>\mathrm{M}\mathrm{n}{\mathrm{O}}_4^{-}>\mathrm{C}{\mathrm{r}}_2{\mathrm{O}}_7^{2-}$