What is the equivalent weight of $K_2Cr_2O_7$ during the iodometric standardization of $Na_2S_2O_3$?

In the balanced reaction $x\,MnO_4^- + y\,H_2O \to 2Mn^{2+} + 5H_2O + 9O_2 + z\,e^-$,what are the values of $x$,$y$,and $z$?

Write the balanced chemical equations for the following reactions:
$(1)$ Reaction of $Cr_2O_7^{2-}$ with $Fe^{2+}$ in acidic medium.
$(2)$ Reaction of $MnO_4^-$ with $Fe^{2+}$ in acidic medium.

For the following balanced equation,$x, y$ and $z$ will be respectively:
$xMnO_4^- + yH^+ + ze^- \to 2Mn^{2+} + 4H_2O$

Assign $A, B, C, D$ from the given types of reactions:
$A$: Disproportionation reaction.
$B$: Comproportionation reaction.
$C$: Either intermolecular redox reaction or displacement reaction.
$D$: Either thermal combination redox reaction or thermal decomposition redox reaction.
Reaction: $MnO_4^- + H^+ + Br^- \longrightarrow Mn^{2+}(aq.) + Br_2 \uparrow$

Which of the following reactions is a redox reaction?