Question

Which of these is not a monomer for a high molecular mass silicone polymer ?

• A. MeSiCl₃
• B. Me₂SiCl₂
• C. Me₃SiCl
• D. PhSiCl₃

Answer 1

The Correct Option is C

The question asks which of the given compounds is not a monomer for a high molecular mass silicone polymer. To solve this, we need to understand what comprises a monomer suitable for silicone polymer formation.

Silicone polymers, also known as polysiloxanes, are generally formed by hydrolysis and subsequent polymerization of organosilicon chlorides. A typical silicone polymer is a silicon-oxygen backbone with organic groups attached to the silicon atoms. The following options are given:

• \text{MeSiCl}_3 \right): This has only one organic group (Me = Methyl) attached to silicon, and can form a networked, cross-linked structure because of three chlorine groups capable of hydrolysis.
• \text{Me}_2\text{SiCl}_2 \right): This has two organic groups and two chloride groups, allowing linear polymer formation.
• \text{Me}_3\text{SiCl} \right): This compound has three methyl groups attached to silicon, leaving only one chloride group. This structure is not conducive to forming high molecular mass linear or 3D network polymers, as it cannot form extended chains or networks effectively.
• \text{PhSiCl}_3 \right): Similar to MeSiCl₃ but with a phenyl group instead of a methyl, it supports cross-linking and network polymer formation.

Therefore, the compound \text{Me}_3\text{SiCl} is not suitable as a monomer for high molecular mass silicone polymers because it cannot facilitate sufficient network formation. It primarily acts as an end-capping agent.

The correct answer is Me₃SiCl.