Write the general and empirical formula of silicone.

It is observed that $Pb^{2+}$ is more stable than $Pb^{4+}$,while $Sn^{2+}$ is less stable than $Sn^{4+}$. Consider the following reactions:
$PbO_{2} + Pb \rightarrow 2PbO; \Delta_{r}G^{\circ} (1)$
$SnO_{2} + Sn \rightarrow 2SnO; \Delta_{r}G^{\circ} (2)$
Identify the correct set from the following.

$A$ large amount of energy is released during the formation of $Al_{2}O_{3}$,which is used in which of the following?

Which of the following salts cannot exist?

Silicon chloroform is prepared by

Mention the catenation order for group $14$ elements.