How many moles of electrons are required to reduce $2.5 \ mol$ of $Cr_2O_7^{2-}$ to $Cr^{3+}$?

Oxidation of thiosulphate $S_2O_3^{2-}$ ion by iodine gives

The product of $I^-$ with $MnO_4^-$ in acidic medium is

Assign $A, B, C, D$ from the given type of reaction.
$Fe^{2+}(aq.) + Cr_2O_7^{2-}(aq.) + H^+(aq.) \longrightarrow Fe^{3+}(aq.) + Cr^{3+}(aq.) + H_2O(l)$

When $KMnO_4$ acts as an oxidizing agent and ultimately forms $MnO_4^{2-}$,$MnO_2$,$Mn_2O_3$,and $Mn^{2+}$,what will be the number of electrons transferred in each case,respectively?

The number of electrons involved in the reduction of permanganate to manganese dioxide in acidic medium is $.......$.