Holme's signals can be given by using

Which of the following is/are ionic in nature?
$(i)$ $GeF_4$ $(ii)$ $SnF_4$ $(iii)$ $PbF_4$

An oxide of an element is a gas and dissolves in water to give an acidic solution. The element belongs to:

At high temperature,nitrogen combines with $CaC_2$ to give:

The gas which turns lime water milky is

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 $(sp^2)$.