$A$ thin film of aluminum deposited on glass acts as a good mirror because ...............

Which of the following statements are correct?
$1.$ Charcoal can be obtained by heating wood in the absence of air.
$2.$ Charcoal is an impure form of graphite.
$3.$ Diamond is thermodynamically the most stable allotrope of carbon.
$4.$ Coke is used as an oxidising agent during the extraction of iron from its ores.

Among the following elements, $X$ exhibits maximum catenation and $Y$ is the least abundant on earth. $X$ and $Y$ elements are

Which among the following is not a property of silicones?

The products formed during the reaction of carbon with conc. $H_2SO_4$ are:
$C + 2H_2SO_4 \longrightarrow \text{products}$

Which one of the following statements about allotropes of carbon is incorrect?