How many moles of electrons are needed to convert one mole of nitrate ion to hydrazine?

Consider the reaction of water with $F_{2}$ and suggest,in terms of oxidation and reduction,which species are oxidized and which are reduced.

Consider the following reaction occurring in basic medium $2MnO_4^- (aq) + Br^- (aq) \to 2MnO_2 (s) + BrO_3^- (aq)$. How can the above reaction be balanced further?

For the redox reaction $Zn + NO_3^{-} \rightarrow Zn^{+2} + NH_4^{+}$,the coefficients of $NO_3^{-}$,$Zn$,and $H^{+}$ in the balanced equation are respectively:

In the half-reaction $Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$,the equivalent weight of $Cr_2O_7^{2-}$ is obtained by dividing its molecular weight by:

Manganese ions $(Mn^{2+})$ can be oxidised by persulphate ions $(S_2O_8^{2-})$ according to the following half-equations:
$S_2O_8^{2-} + 2e^- \longrightarrow 2SO_4^{2-}$
$Mn^{2+} + 4H_2O \longrightarrow MnO_4^- + 8H^+ + 5e^-$
How many moles of $S_2O_8^{2-}$ are required to oxidise $1 \ mole$ of $Mn^{2+}$?