In the reaction of oxalate with permanganate in acidic medium,the number of electrons involved in producing one molecule of $CO_2$ is

Assign $A, B, C, D$ from the given type of reaction.
$Sn + PCl_5 \xrightarrow{\Delta} SnCl_4 + PCl_3$

Assign $A, B, C, D$ from the given type of reaction for the following chemical equation:
$N_2 + 3H_2 \longrightarrow 2NH_3$

In an alkaline medium,$ClO_2$ oxidizes $H_2O_2$ to $O_2$ and is reduced to $Cl^-$. How many moles of $H_2O_2$ will be oxidized by $1$ mole of $ClO_2$?

In acidic medium,iodide $(I^{-})$ is oxidized to iodine $(I_2)$ by $KMnO_4$. What is the change in the oxidation number of manganese in this reaction?

Identify the elements undergoing reduction and oxidation respectively in the following redox reaction.
$3 H_3AsO_{3(aq)} + BrO_{3(aq)}^{-} \rightarrow Br_{(aq)}^{-} + 3 H_3AsO_{4(aq)}$