Glass reacts with $HF$ to produce

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{C}Cl_4 + H_2O \longrightarrow \text{No reaction}$

Which of the following statements are correct?
$1.$ Charcoal can be obtained by heating wood in the absence of air.
$2.$ Charcoal is an impure form of graphite.
$3.$ Diamond is thermodynamically the most stable allotrope of carbon.
$4.$ Coke is used as an oxidising agent during the extraction of iron from its ores.

What is the value of $\angle S-S-S$ in the puckered $S_8$ ring of rhombic sulfur (in $^{\circ}$)?

$Si_2O_7^{6-}$ anion is obtained when

Match the items in Column $I$ with its main use listed in Column $II$.

Column $I$	Column $II$
$A$. Silica gel	$i$. Transistor
$B$. Silicon	$ii$. Ion-exchanger
$C$. Silicone	$iii$. Drying agent
$D$. Silicate	$iv$. Sealant