In which of the following sets are allotropes of carbon correctly matched with their uses?
$i$. graphite - crucibles
$ii$. activated charcoal - water filters
$iii$. carbon black - fuel
The correct answer is

Which of the following statements are correct?
$(a)$ The isotope of carbon containing $7$ neutrons has natural abundance of $1.1 \%$.
$(b)$ Among the $IV$ $A$ group elements, $Sn$ has the lowest melting point.
$(c)$ Silicon is the $2^{nd}$ (by mass) most abundant element in the earth's crust.
$(d)$ Elemental carbon shows the highest electrical resistivity among the $14$ group elements.

Among the given group $14$ elements,the one with highest density is

$A$ cyclic skeleton of silicon and oxygen can be constructed by the silicate ion composition:

Which of the following compounds forms silicones on hydrolysis?

What do $C$ and $Si$ possess among the following?