Paper: CSIR-NET June 2019 · Subject: Inorganic Chemistry · Chapter: Main Group Elements · Topic: Main Group Elements – General · Marks: 2 · Difficulty: Medium
In the synthesis of polydimethylsiloxane, the chain forming, branching and terminating agents respectively, are
(a)$\mathrm{Me}_{2} \mathrm{SiCl}_{2}, \mathrm{Me}_{3} \mathrm{SiCl}$ and $\mathrm{MeSiCl}_{3}$
(b)$\mathrm{Me}_{2} \mathrm{SiCl}_{2}, \mathrm{MeSiCl}_{3}$ and $\mathrm{Me}_{3} \mathrm{SiCl}$
(c)$\mathrm{MeSiCl}_{3}, \mathrm{Me}_{2} \mathrm{SiCl}_{2}$ and $\mathrm{Me}_{3} \mathrm{SiCl}$
(d)$\mathrm{Me}_{2} \mathrm{SiCl}_{2}, \mathrm{MeSiCl}_{3}$ and $\mathrm{Me}_{4} \mathrm{Si}$
Answer
Answer: B ✓ checked by 4AB · confidence high
Explanation
Me₂SiCl₂ builds the linear –O–SiMe₂–O– chain, MeSiCl₃ introduces branch points (three Si–O bonds) and Me₃SiCl caps the chain ends.