Acidified potassium dichromate on reacting with a sulphite is reduced to

What is the stoichiometric coefficient of the oxalate ion after balancing the following redox reaction?
$MnO_4^- + C_2O_4^{2-} + H^+ \rightarrow Mn^{2+} + CO_2 + H_2O$

Assertion: Change in color of acidic solution of potassium dichromate by breath is used to test drunk drivers.
Reason: Change in color is due to the complexation of alcohol with potassium dichromate.

$ClO_2$ oxidizes $H_2O_2$ to $O_2$ in basic medium and is itself reduced to $Cl^-$. How many moles of $H_2O_2$ will be oxidized by one mole of $ClO_2$ (in $.5$)?

$KMnO_4$ acts as an oxidising agent in alkaline medium. When alkaline $KMnO_4$ is treated with $KI$,iodide ion is oxidized to

If the number of moles of $Fe^{2+}$ ions oxidized by one mole of acidified $MnO_4^{-}$ is $x$, the number of moles of $Fe^{2+}$ ions oxidized by one mole of acidified $Cr_2O_7^{2-}$ is: