What is produced by the hydrolysis of $(Me)_2SiCl_2$?

The element $X$ which forms a stable product of the type $XCl_4$ is $....$

The common basic structural unit in silicates and silica is

The element similar to carbon is

Explain the following:
$(a)$ $CO_2$ is a gas whereas $SiO_2$ is a solid.
$(b)$ Silicon forms $SiF_6^{2-}$ ion whereas corresponding fluoro compound of carbon is not known.

Identify the correct statements from the following.
$i$. Melting points and boiling points of group $13$ elements are much higher than those of corresponding group $14$ elements.
$ii$. $SiO$ only exists at high temperatures.
$iii$. $PbI_4$ does not exist.
$iv$. Buckminster fullerene contains twelve $6$-membered carbon rings and twenty $5$-membered carbon rings.