Question

The chain length of the silicone polymer can be controlled by adding
A.$MeSiC{l_3}$
B.$M{e_2}SiC{l_2}$
C.$M{e_3}SiCl$
D.$M{e_4}Si$

Answer 1

Hint: To answer this question, you should recall the concept of silicon polymers. They are also known as polysiloxanes. The $Si - Si$ linkages are analogous to $C - C$ bonds in organic compounds.

Complete step by step answer:
Silicone polymers involve units of silicoane. Silicoane is a chain of alternating oxygen and silicon atoms which are interspersed with combinations of hydrogen, carbon and other inert species. These polymers have many industrial uses and are important components of safety pieces of equipment. The chain length of the silicone polymer can be controlled by adding \[M{e_3}SiCl\].
The reaction of this sequence can be represented as:
\[R \cdot + M{e_3}SiCl \to M{e_3}Si - R + Cl \cdot \].
This blocks the end of the silicon polymer and thus terminates the chain propagation.
This is followed by the combination of rest free radicals \[2Cl \cdot \to C{l_{2}}\].

Therefore, the correct answer to this question is option C.

Note:
Other important types of silicates found in nature include:
Ortho silicates (or Nesosilicates): The orthosilicate ion is the strong conjugate base of weak orthosilicic acid as well as it will not persist in aqueous solutions. In nature, orthosilicates are rare and only found with cations which form highly insoluble salts.
Pyro silicate (or Sorosilicates)
Cyclic silicates (or Ring silicates)
Chain silicates (or pyroxenes)
Double chain silicate (or amphiboles)
Sheet or phyllosilicates
Three dimensional (or tecto) silicates