The formation of $Al_2O_3$ involves the evolution of a large quantity of heat,which makes its use in:

In the laboratory,silicon can be prepared by the reaction of:

The silicate anion in the mineral kinoite is a chain of three $SiO_4$ tetrahedra that share corners with adjacent tetrahedra. The mineral also contains $Ca^{2+}$ ions,$Cu^{2+}$ ions,and water molecules in a $1 : 1 : 1$ ratio. The mineral is represented as:

Which one of the following is a semiconductor?

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.

The element that does not show catenation is