Hydrolysis of which of the following carbides does not take place?

The number of amphoteric oxides from the following is
$CO_2, GeO_2, SnO_2, PbO_2, CO, GeO, SnO, PbO$

How many corners of $SiO_4$ units are shared in the formation of three dimensional silicates?

The oxidation state shown by silicon when it combines with strongly electropositive metals is

Identify the correct statements among the following:
$a$) $C_{60}$ molecule has $12$ five-membered rings and $20$ six-membered rings.
$b$) $H_2CO_3 / HCO_3^-$ buffer system helps to maintain $pH$ of blood between $7.26$ and $7.42$.
$c$) Graphite is used as a dry lubricant in machines running at high temperatures.

Which of the following statements are correct?
$i$. The basic structural unit of silicates is $SiO_4^{4-}$
$ii$. Silicones are biocompatible
$iii$. Producer gas contains $CO$ and $N_2$
The correct option is