Identify $(P)$ and $(Q)$ in the following reaction:
$2 CH_3 Cl + Si$ $\xrightarrow[570 \ K]{\text{Cu powder}} (P)$ $\xrightarrow{H_2 O} (Q)$ $\longrightarrow \text{Straight chain polymer}$

Match the following:

List-$I$ (Compound)	List-$II$ (Use)
$A$. Kieselghur	$I$. Chromatographic material
$B$. Silica gel	$II$. Softening of hard water
$C$. $ZSM-5$	$III$. Filtration plants
$D$. Hydrated zeolites	$IV$. To convert alcohol directly into gasoline

Which metal is used in radiation shields?

The treatment of zinc with very dilute nitric acid produces

The chloride that $can \ not$ get hydrolysed is

$A$ compound $A$ is used in paints instead of salts of lead. Compound $A$ is obtained when a white compound $B$ is strongly heated. The compound $B$ is insoluble in water but dissolves in $NaOH$ solution,forming a solution of compound $C$. The compound $A$ on heating with coke gives a volatile metal $D$ and a gas $E$ which burns with a blue flame. Identify the possible species $D$ and $C$ respectively.