Assuming complete ionization, same moles of which of the following...

${MnO}_{4}^{-} ⟶ Mn^{2 +}$ ; Change in oxidation no. = 5

In option,

i. $Fe^{2 +} ⟶ Fe^{3 +}$

Change in oxidation no. = 1

ii. $Fe^{2 +} ⟶ Fe^{3 +}$

Change in oxidation no. = 1

${SO}_{3}^{2 -} ⟶ {SO}_{4}^{2 -}$

Change in oxidation no. = 2

$= 1 + 2 = 3$

iii. $Fe^{2 +} ⟶ Fe^{3 +}$

Change in oxidation no. = 1

${C}_{2}{O}_{4}^{2 -} ⟶ 2C{O}_{2}$

Change in oxidation no. = 2

$= 1 + 2 = 3$

iv. $Fe^{2 +} ⟶ Fe^{3 +}$

Change in oxidation no. = 1

$2{NO}_{2}^{-} ⟶ 2{NO}_{3}^{-}$

Change in oxidation no. = 4

$= 1 + 4 = 5$