Assign $A, B, C, D$ from the given type of reaction.
$2KI + HgI_2 \downarrow \longrightarrow K_2[HgI_4]$

For the reaction: $4Fe + 3O_2 \rightleftharpoons 4Fe^{3+} + 6O^{2-}$,which of the following statements is $NOT$ correct?

$CO_2$ and $SO_2$ gases can be distinguished by using:

$KMnO_4$ acts as an oxidising agent in acidic medium. $X$ is the difference between the oxidation states of $Mn$ in reactant and product. $Y$ is the number of $d$ electrons present in the brown red precipitate formed at the end of the acetate ion test with neutral ferric chloride. The value of $X+Y$ is $.........$

$50 \ cm^{3}$ of $0.04 \ M \ K_{2}Cr_{2}O_{7}$ in acidic medium oxidizes a sample of $H_{2}S$ gas to sulphur. The volume of $0.03 \ M \ KMnO_{4}$ required to oxidize the same amount of $H_{2}S$ gas to sulphur in acidic medium is: (in $cm^{3}$)

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Cu^{2+} (aq.) + 2I^{-} \longrightarrow CuI \downarrow + \frac{1}{2}I_2$