What is the result of the reaction between $KMnO_4$ and $HCl$?

Consider the following equations:
$2 Fe^{2+} + H_2O_2 \rightarrow x A + y B$
(in basic medium)
$2 MnO_4^{-} + 6 H^{+} + 5 H_2O_2 \rightarrow x' C + y' D + z' E$
(in acidic medium)
The sum of the stoichiometric coefficients $x, y, x', y'$ and $z'$ for products $A, B, C, D$ and $E,$ respectively,is............

In alkaline condition $KMnO_4$ reacts as follows:
$2KMnO_4 + 2KOH \to 2K_2MnO_4 + H_2O + O$
Therefore,its equivalent weight will be:

The reaction of white phosphorus on boiling with alkali in an inert atmosphere results in the formation of product '$A$'. The reaction of $1 \ mol$ of '$A$' with an excess of $AgNO_3$ in an aqueous medium gives ............... $mol(s)$ of $Ag$. (Round off to the Nearest Integer).

If an iron rod is dipped in $CuSO_4$ solution,what happens?

Aqueous solutions of $Na_2S_2O_3$ on reaction with $Cl_2$ gives