Question

Give reasons for the following:

A) $CC{l}_4$ is immiscible in water, whereas $SiC{l}_4$ is easily hydrolysed

B) Carbon has a strong tendency for catenation compared to silicon.

Answer 1

a) i) In $CC{l}_4$, C is the central atom

ii) It is nonpolar covalent compound and water is a polar solvent. We know like dissolves like. Thus, $CC{l}_4$ cannot be dissolved in water.

iii) Also, the Carbon atom does not have empty $d$-orbitals like other group $14$ elements to accommodate the lone pair of electrons from the oxygen atom of water molecules. So, it doesn’t undergo hydrolysis with water.


In $CC{l}_4$, C is the central atom

It is nonpolar covalent compound and water is a polar solvent. We know like dissolves like. Thus,$CC{l}_4$ cannot be dissolved in water.

Also, the Carbon atom does not have empty d-orbitals like other group $14$ elements to accommodate the lone pair of electrons from the oxygen atom of water molecules. So, it doesn’t undergo hydrolysis with water.

Properies of $SiC{l}_4$

In $SiC{l}_4$, Si has empty 3d orbital and undergoes hydrolysis by accepting a lone pair of electrons from water molecule to form $Si(OH{)}_4$ . It is shown as given below

b) Carbon atoms have the tendency to link
with one another through covalent bonds to
form chains and rings which is called
catenation. This is because $C—C$ bonds are
very strong. Down the group the size increases and electronegativity decreases and thereby, tendency to show catenation decreases. This can be clearly seen from bond enthalpies values i.e. $348KJmo{l}^{-1}$ for $C-C$ while $297KJmo{l}^{-1}$ for $Si-Si$. Hence, we can say that carbon have strong tendency to undergo catenation than silicon.