What is the charge required to convert $2 \ mol$ of $KMnO_4$ to $MnSO_4$ (in $F$)?

In acidic medium,$K_2Cr_2O_7$ shows oxidising action as represented in the half reaction:
$Cr_2O_7^{2-} + XH^+ + Ye^- \rightarrow 2A + ZH_2O$
$X, Y, Z$ and $A$ are respectively:

Write the net ionic equation for the reaction of potassium dichromate$(VI)$,$K_{2}Cr_{2}O_{7}$ with sodium sulphite,$Na_{2}SO_{3}$ in an acidic solution to give chromium$(III)$ ion and the sulphate ion.

In the equation,$BiO_3^{-} + 6H^{+} + xe^{-} \rightarrow Bi^{3+} + 3H_2O$. What is the value of $x$?

Which of the following reactions is a redox reaction?

$aIO_3^- + bI^- + 6H^+ \to cI_2 + 3H_2O$
In the above reaction,the coefficients $a$,$b$,and $c$ are respectively: