The catenation tendency of $C, Si$ and $Ge$ is in the order $Ge < Si < C$. The bond energies (in $kJ \ mol^{-1}$) of $C-C, Si-Si$ and $Ge-Ge$ bonds, respectively, are:

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

Consider the following statements:
$I$. In diamond,each carbon atom is $sp^3$-hybridised.
$II$. Graphite has planar hexagonal layers of carbon atoms.
$III$. Silicones being surrounded by non-polar alkyl groups are water repelling in nature.
$IV$. The order of catenation in group $14$ elements is $Si > C > Sn > Ge > Pb$.
The correct statements are:

Silicon dissolves in excess of $HF$ due to the formation of:

$PbO_2$ reacts with concentrated $HNO_3$. The gas evolved is:

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{C}Cl_4 + H_2O \longrightarrow \text{No reaction}$