What is obtained by the reaction of $N_2$ with calcium carbide $(CaC_2)$?

Choose the correct statements about allotropes of carbon:
$I$. Graphite has a layered structure.
$II$. Buckminsterfullerene is not aromatic in nature.
$III$. The distance between two adjacent layers in graphite is $340 \ pm$.
$IV$. The hybridization of carbons in graphite and Buckminsterfullerene is the same $(sp^2)$.

The repeating unit in silicone is

When graphite is subjected to an electric arc in the presence of an inert atmosphere,it gives:

Which of the following substances is acidic?

Lead is present in maximum quantity in which of the following types of glass?