Give reasons for the following:
$(i)$ $CCl_4$ is immiscible in water,whereas $SiCl_4$ is easily hydrolyzed.
$(ii)$ Carbon has a strong tendency for catenation compared to silicon.

(N/A) $(i)$ $CCl_4$ is a non-polar covalent compound and cannot form hydrogen bonds with polar $H_2O$ molecules. Furthermore,$C$ does not have vacant $d$-orbitals to accommodate the lone pair of electrons from the oxygen atom of the water molecule,making it resistant to hydrolysis.
In contrast,$SiCl_4$ is easily hydrolyzed by water because the central $Si$ atom has vacant $d$-orbitals that can accommodate the lone pair of electrons from the oxygen atom of the water molecule. The hydrolysis reaction is as follows:
$SiCl_4 + 4H_2O \rightarrow Si(OH)_4 + 4HCl$
$(ii)$ Carbon atoms have a strong tendency to link with one another through covalent bonds to form long chains and rings; this property is called catenation. This is primarily because the $C-C$ bond enthalpy is very high,making the bond exceptionally strong. As we move down the group,the atomic size increases and electronegativity decreases,which leads to a significant reduction in the bond strength and,consequently,the tendency for catenation decreases. The order of catenation is $C \gg Si > Ge > Sn$. Lead $(Pb)$ does not show catenation.